for review only - university of toronto t-spacefor review only 3 strow et al. [8] who reported line...
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Analysis of Fourier transform spectra of N2O in the v3 band
for atmospheric composition retrievals
Journal: Canadian Journal of Physics
Manuscript ID cjp-2017-0303.R2
Manuscript Type: Article
Date Submitted by the Author: 09-Dec-2017
Complete List of Authors: Predoi-Cross, Adriana; Home, 512 Silkstone Crescent West; University of Lethbridge, Physics and Astronomy Hashemi, Robab; University of lethbridge, Physics and Astronomy; Harvard-Smithsonian Center for Astrophysics, Atomic and Molecular Physics Division Devi, V. Malathy; The College of William and Mary
Naseri, Hossein; University of Lethbridge Faculty of Arts and Science, Physics and Astronomy; Farmers Edge Smith, Mary Ann; Science Directorate, NASA Langley Research Center, Science Directorate
Keyword: N2O, air-broadening, intensities, pressure induced shift, line mixing coefficients
Is the invited manuscript for consideration in a Special
Issue? : Ursula Franklin commemorative Festschrift
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Analysis of Fourier transform spectra of N2O in the νννν3 band for atmospheric composition retrievals
Adriana Predoi-Cross, Robab Hashemi, V. Malathy Devi, Hossein Naseri,
and Mary Ann H. Smith
Adriana Predoi-Cross.1 Dept. of Physics & Astronomy, University of Lethbridge, Alberta T1K 3M4,
Canada. Present address: 512 Silkstone Crescent West, Lethbridge, Alberta T1J 4C1, Canada.
Robab Hashemi. Dept. of Physics & Astronomy, University of Lethbridge, Alberta T1K 3M4, Canada.
Present address: Harvard-Smithsonian Center for Astrophysics, Atomic and Molecular Physics Division,
Cambridge, Massachusetts 02138, USA
V. Malathy Devi. Dept. of Physics, College of William and Mary, Williamsburg, Virginia 23187, USA.
Hossein Naseri. Dept. of Physics & Astronomy, University of Lethbridge, Alberta T1K 3M4, Canada.
Present address: Farmers Edge, 4309 8 Ave N, Lethbridge, Alberta, Canada
Mary Ann H. Smith. Science Directorate, NASA Langley Research Center, Hampton, Virginia 23681,
USA.
1Corresponding author: E-mail: [email protected].
Abstract
We report measurement results for line positions, intensities, half-width and pressure induced shift
coefficients and line mixing coefficients for N2O broadened by air in the ν3 band. The high signal-to-
noise ratio spectra have been recorded at high resolution using the McMath-Pierce Fourier Transform
Spectrometer (FTS) formerly located at the National Solar Observatory on Kitt Peak, AZ, USA. The
spectra were analyzed using a multispectrum nonlinear least squares curve fitting technique employing the
speed-dependent Voigt profile with a Rosenkranz (weak) line mixing component. The speed dependence
parameters were calculated as suggested in the study of Kochanov (2017). Several comparisons have been
performed between the retrieved parameters and previously published results. For |m| ≤ 40, our results for
line positions, broadening and line mixing coefficients agree best with the results of Loos et al. (2015).
Also, we compared the obtained line positions and intensities with the corresponding values in HITRAN
2016 and GEISA 2015 databases. No significant or systematic differences were noticed. The precision of
our line positions was estimated to be 3×10-5
cm-1
. The reported line positions, intensities and air-
broadening coefficients are accurate to better than 2%. The accuracy of air-pressure induced line shifts
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and line mixing coefficients is better than 5%. The line mixing coefficients and air-broadening
coefficients were also calculated using the Exponential Power Gap (EPG) scaling law, and these
calculated values were found to be in good agreement with the experimental results.
Key words: N2O, air-broadening, positions, intensities, pressure induced shift, line mixing coefficients,
multispectrum nonlinear fit.
1. Introduction
It is well documented that gases included in the NxOy family (NO, NO2, N2O2, N2O, etc.) play a
crucial role in terrestrial atmospheric chemistry. For example, these gases are produced during lightning,
as a result of reaction of nitrogen and oxygen in air. In highly inhabited areas with heavy traffic, the
production of nitrogen oxides is higher, leading to occurrences of acid rain and smog. As one of the
greenhouse gases, nitrous oxide (N2O) is important in radiative transfer [1]. Accurate laboratory
spectroscopic studies of molecular line shapes in different spectral ranges are needed to enable satellite-
based, ground-based and air-borne remote sensing measurements of N2O concentrations. To meet this
demand, we present spectroscopic results of measured line intensities and line shape parameters to
validate and update the existing knowledge and information on line parameters for the mixture of N2O
with air, stored in databases such as HITRAN2016 [2].
Previous studies of nitrous oxide broadened by N2, O2, and N2O include the one by Lacome et al. [3]
who had analyzed the Fourier transform spectra to obtain self-, N2- and O2-broadened line parameters of
N2O and the temperature dependences for the corresponding line-width coefficients in the 4- and 8-µm
spectral regions. Toth [4] published N2- and air-broadened line-widths and frequency-shifts for spectral
lines in the 1800 to 4800 cm-1
range. In a separate study, the author reported the self-broadened line-
widths and pressure-induced line shifts of N2O in the 1800-2630 cm-1
region [5]. Nemtchinov et al. [6]
have studied N2- and O2-broadened half-widths and their temperature dependences between 216 and 296
K for spectral lines in the 4.5 µm region corresponding to the ν3 fundamental band of N2O, but they did
not determine the pressure-induced line shifts.
Vitcu et al. [7] have investigated 0310←0110 parallel Q-branch of N2O at 297 K and over the pressure
range of 11 to 30 Torr to measure self- broadening, pressure-induced shifts, and line mixing coefficients.
The line mixing effects for N2O have also been the focus of other line-shape studies such as the one by
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Strow et al. [8] who reported line mixing in the ν2 + ν3 Q-branch of N2O. Margottin-Maclou et al. [9]
observed line mixing effects in N2O absorption spectra recorded at room temperature using a Fourier
transform spectrometer (FTS). Loos et al. [10] have reported highly accurate room temperature
measurements of air-broadening, pressure-shift, speed dependence and Rosenkranz line mixing parameters
for transitions in the ν3 fundamental band of N2O. Hartmann et al. [11] also have examined line mixing
in N2O Q-branches, broadened by N2, O2, and air, both in the laboratory environment and in atmospheric
spectra.
In this study, we investigate the deviations of air-broadened spectral line shapes in the ν3 band of N2O
from the Voigt profile (VP) [12] using the quadratic Speed Dependent Voigt line profile (qSDV) [13] and
taking Rosenkranz line mixing into account. We also performed EPG calculations to estimate the weak
line mixing effects in the Rosenkranz approximation [7,8].
2. Experimental Details
The N2O spectra were all recorded in November 2002, covering the 600-2850 cm-1
spectral range
using the McMath-Pierce FTS located at the National Solar Observatory on Kitt Peak, and the “Langley”
50-cm coolable sample cell. We have used the same experimental setup as the one used in Ref [15] and for
further details in the measurement of temperature and pressure, we refer to the experimental section in Ref
[15]. The spectral resolution was 0.006 cm−1. A globar source, KCl beamsplitter, liquid-helium-cooled
arsenic-doped silicon detectors, and InAs and cooled CaF2 filters were used in the experiment. The
experimental conditions of spectra analyzed are presented in Table 1. Four spectra were recorded using
mixtures of the N2O and air at room temperature, and a low pressure spectrum of pure N2O was recorded
at 294 K. In Figure 1, an example of an experimental spectrum recorded at low pressure is shown.
The sample pressures for all spectra were monitored continually using periodically calibrated
Baratron gauges of appropriate pressure range. A commercially purchased natural sample of N2O with a
stated purity of 99.0 % (minimum purity) was used to obtain the spectra. For air-broadened spectra the high-
purity N2O samples were mixed with known amounts of a commercially-obtained air sample to obtain the
volume mixing ratios of N2O listed in Table 1.
The interferograms were properly oversampled at the experimental resolution (0.006 cm-1
) and the
spectra were appropriately pressure broadened. For wavenumber calibration purposes, the positions of
residual water vapor transitions of the ν2 band appearing within the filter band pass of 1200-2800 cm−1
were used [2]. Any residual water (less than 1%) in the cell could have come from either the N2O or air
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samples (or both). The main components of the water spectral features arising from outside the sample
cell would be the strong narrow lines from residual gas in the evacuated FTS tank, and the broad features
from the atmospheric-pressure optical path (mainly between the globar source and the cell) purged with
dry nitrogen. There might also be a very small component from the short (few cm) paths between the
windows of the 50-cm cell and its evacuated enclosure. We did not observe any contribution attributable
to water inside the sample cell or the cell enclosure, and the positions of the strong narrow water vapor
lines from the FTS tank were used for the calibration of the wavenumber scales of the N2O spectra. This
calibration has been further fine-tuned using self-calibration with respect to the positions of N2O
transitions in HITRAN2016 [2]. Note that the background spectra were not used to ratio the pressure-
broadened spectra, but only to identify the residual H2O features.
3. Spectroscopic analysis
We performed the analysis of spectra in the spectral interval of 2120-2260 cm−1
of the ν3 band.
The multispectrum fitting program “Labfit” [16] was used to retrieve the spectroscopic parameters by
fitting short spectral intervals (4 or 5 cm−1
) to cover the entire band. The line parameters were derived
using the quadratic speed dependent Voigt line shape model. The instrumental line shape was modeled
considering the finite size of the aperture, the sinc function and the apodization used. The user-interactive
“Labfit” program fits the baseline to a polynomial, in this case a 9th
order polynomial, for each fitted
interval. More details of the fitting software are in the Appendix of Ref. [16]. Deviations from the 100%
level of transmittance of the spectra (i.e. baseline), due the detector non-linearity and the source’s stability,
are taken into account because the accuracy of the line parameters depends on the knowledge of the 100%
transmittance level, zero level, and the background of the spectra. The software accounts for the zero level
offsets by considering them as fitted parameters.
For every fitted spectral line, the multispectrum fitting technique is able to retrieve the following
line parameters from the 5 spectra: line position, intensity, air-broadened line-width, air-induced pressure
shift coefficient, and the speed dependence parameter. The apodization was applied because at low
pressures, the widths of the N2O lines were smaller than or comparable with that of the instrumental line
shape, and the side lobes of the sinc functions were visible in the spectra. The software uses a modified
Levenberg-Marquardt [17, 18] algorithm for minimizing the sum of the squares of the residuals between
the simulated and the observed spectra; full details are described in Ref. [16] and its Appendix.
Due to the high density of transitions in the spectral region of present study, the spectra were fitted
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in short spectral intervals (4 to 5 cm−1
) beginning with the lowest-pressure spectrum, and adding higher-
pressure spectra one at a time. In Figure 2, in the top panel, the overlaid experimental spectra are plotted.
The bottom panel presents the weighted fit residuals (Observed-Calculated). The fit residuals were
minimized by using the qSDV model and a weak line mixing component. After the initial fit the spectra
were given weights calculated as the ratios between the overall standard deviation and the standard
deviations of individual fitted spectra. The software was displaying both the overall standard deviations
and the ones for individual spectra.
The following formulae were used to retrieve the broadening and pressure shift coefficients:
����, �� = � ��������1 − �� ���� ��� + ��������� ���� �
��� (1) ∆!"=Ptot[δo(air)(1-χ)+δo(self)χ] (2) #��� = #��� + #%�� − �&� (3)
where ����, �� is the Lorentz half-width at pressure P and temperature T, Ptot is the total sample pressure, χ is the volume mixing ratio of N2O, and δ
o represents the pressure-shift coefficient (in
cm−1
atm−1
). �� is the Lorentz half-width of the line at the reference pressure Po (1 atm) and reference temperature To (296 K). n1 and n2 represent the temperature dependence exponents of air broadening and
self-broadening, respectively, the observed shift of the line in cm-1
is ∆ν, and the temperature dependence
of pressure induced shift coefficient is denoted by #%. The list of initial values for the line parameters was taken from the HITRAN2016 database [2], with initial values for parameters such as δ' not included in
HITRAN set to zero. By minimizing the statistical errors using the multispectrum fit method, precise line
parameters consistent with all measured spectra can be retrieved.
When we use the qSDV profile [13], the Lorentz width can be described as a function of velocity
as presented in Ref. [19]:
�� = ���'(� )1 + * +, --./0 − 123 (4)
where the speed of the molecular collision is v, vm is the mean speed of the molecular collision, the most
probable speed of the collision is presented by vp, and S is the parameter representing speed dependence in
the equation. The value of 1.5 is taken for constant c [14].
In our study we were not able to retrieve accurate values for the speed dependence parameter for
each transition (the resolution and the S/N of the spectra were not sufficiently high to retrieve individual
values of speed dependence). Hence, we used the calculated speed dependence parameters as described by
Kochanov [20]. The expressions in that paper allow users to compute the speed-dependence parameters
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for different gas mixtures and different values for the exponent q in the effective inter-molecular potential.
We have assumed a value of q = 6 in the expression of effective potential V~r-q
for the N2O-air mixture.
In all fits with the speed dependent Voigt profile we have assumed a value of 0.0895 for the speed
dependence parameter S in Eq. (4). According to Ref. [20] there is no rotational quantum number
dependence for the speed-dependence parameter, even though recent experimental studies such as that of
Loos et al. [10] suggest that there is a rotational quantum number dependence. A constant value of S =
0.0895 has been fixed for all N2O transitions in our fits. We note that this value of the speed dependence
parameter is nearly 10 times larger than the average values obtained by Loos et al. [10].
The asymmetric component that accounts for weak line mixing effects was added to the modelled
line profile. Because the line mixing parameters could not be unambiguously determined for all transitions
from our spectral fits, we chose to use the Exponential Power Gap (EPG) scaling law to calculate the line
mixing coefficients. Considering the collisional transfer of energy that occurs between two energy levels
labelled j and k, in this semi-empirical method we can write that the weak line mixing coefficient, Y o
(T )
is:
45��� = 2 ∑ 898:;":?>"9 (5)
In the equation above @;5 are the off-diagonal elements of the relaxation matrix. The components of the dipole moment are presented by dk and dj , !A5 and !A; are line positions in cm−1. The dipole moment components were calculated from the intensities in HITRAN 2016 [2].
The real parts of the diagonal elements of the relaxation matrix present the air broadening
coefficients in the relaxation matrix formalism, and the off-diagonal elements are related to the
collisional transfer rates κjk, as Wjk = βκjk, where β = 0.418. The value of β was determined such that
the best agreement between the observed and calculated line mixing coefficients, is achieved. By
using the detailed balance relationship, the rate of transfer from state k to j can be connected as follows
to the rate of transfer from j to k:
B5C;5 = B;C5; (6) where ρk is the population of the rotational level k and the expression for ρk can be found in Ref. [21] as
B5 =�2D + 1��EF�?G:HI�� where, KB is the Boltzmann constant in units of cm-1/K. The energy value for each level, Ek, is reported in the HITRAN database [2]. Also, from the sum rule we have:
∑ J;@;5 = 0�L�MN; (7) In the EPG formalism, the collisional transfer rates from the lower rotational level k to a higher
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rotational level j can be written as:
C;5 = ��� OPQG9:PR� S?T �EF �?UPQG9:PHI� �. (8)
where ∆Ejk is the energy gap between the two rotational levels in cm−1
, Bo is the rotational constant in
the lower energy level, and KB is Boltzmann’s constant. Using the nonlinear least squares technique and
the Matlab software, the parameters a, b, and c were optimized. Assuming that the collisional rates are the
same between the upper and lower two vibrational levels, the diagonal elements of the relaxation matrix
can be presented as:
@55 = W0 XY∑ C;5; Z[\\M] + Y∑ C;5; Z�^M]_. (9) We have retrieved the parameters a, b, and c that would best reproduce both the measured air-broadening
and the measured line mixing parameters. They are 0.02757(4), 0.36385(3) and 1.00765(9), respectively.
Since the broadening coefficients do not have a vibrational dependence, we have added to our input files
estimated line mixing coefficients for transitions of N2O belonging to other bands. Since the majority of
these transitions with estimated coefficients had intensities lower by at least one order of magnitude than
the transitions with measured coefficients, it is possible that the influence of implementing calculated
values for line mixing coefficients for weak and very weak transitions is very small, but we believe it
contributed to our low fit residuals.
In addition to the lane shape parameters we also report the experimentally-determined line intensities
and positions for the N2O transitions studied here. As mentioned earlier, the spectra were first calibrated
with respect to line positions belonging to the ν2 band of H2O [2]. The calibration was then improved by
using self-calibration of N2O transitions relative to the N2O line positions in the HITRAN 2016 database
[2]. The retrieved N2O line positions were compared with corresponding values listed in the HITRAN
2016 [2] and the GEISA 2015 database [22], as well as the positions reported in Refs. [6,10], and the
position differences are plotted in Figure 3 as a function of the rotational quantum index m (m = −J in the
P branch and J+1 in the R branch, where J is the lower-state rotational quantum number). Our line
positions agree very well with the values in the HITRAN 2016 and GEISA 2015 databases, as quantified
by the low RMS difference values 1.357×10-6
cm-1
and 1.351×10-6
cm-1
, respectively. The range of values
for the index m is narrower for the study of Loos et al. [10] (i.e. |m| ≤ 40) than the range for m in our study
(|m| ≤ 55) and in the HITRAN and GEISA databases. The line positions from Ref. [10] (which are
actually the HITRAN2012 values [23]) agree best with our retrieved line positions, as shown by Figure 3.
The scatter in these differences is also very low (RMS of 6.228 × 10-7
cm-1
). The retrieved line positions
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are from the present work are listed in Table 2.
As stated earlier, we also retrieved the line intensities for ν3 N2O transitions with |m| ≤ 55. In
Figure 4 we present our results and how they compare with the line intensities from the HITRAN 2016
and GEISA 2015 databases and from the intensities reported by Nemtchinov et al. [6]. We compare the
line intensities by plotting the percentage differences between the results of present study for the qSDV
profile and the values from the other sources ((Other Value − PS)×100/PS). There is more scatter in the
difference values obtained for the P-branch due to the overlap between transitions of the ν3 band and
transitions from other N2O bands (see Figure 1). Panel (B) of Figure 4 compares the line intensities results
through ratios between database or Nemtchinov et al. values and our corresponding retrieved line
intensities. The RMS values for the ratios of our line intensities to HITRAN and GEISA database values
are 8.32×10-3
and 7.98×10-3
, respectively. The lack of a clear m-dependent pattern in the ratio values
plotted in panel (B) suggests that there is no systematic difference between the sets of intensity results
compared, other than our retrieved intensities being (on average) about 1.2% smaller than HITRAN and
GEISA values and 2% smaller than the Nemtchinov et al. values.
The present results for air-broadening and air-shift coefficients are listed in Table 2, and they are
plotted in Figures 5 and 6 along with previous measurements [3,4,6,10], database values [2,22], and
values from the EPG calculation. The present results plotted in Figure 5 also include a set of air-
broadening coefficients retrieved using the Voigt profile (VP) with a line mixing component. Figure 5
shows that the measured results for air-broadening coefficients obtained from our spectra using the qSDV
profile are slightly larger (about 1 %) than the air-broadening values obtained from the same spectra using
VP. An examination of Figure 5 (B) shows that our PS(SDV) measured air-broadening coefficients are
larger than those obtained by Lacome et al. [3], Toth [4], , and Nemtchinov et al. [6] that were all
retrieved using the Voigt profile. As expected, the best agreement (within ± 0.5% or better) is with the
values published by Loos et al. [10], also obtained using the SDV profile and accounting for line mixing.
We note that our measurements cover a slightly larger range of |m| values than Ref. [10]. At high |m|
values (above 40-45) our experimental values are significantly different than the values listed in the
current databases [2,22]. We note that the HITRAN2016 [2] N2O air-broadened widths are the same as in
HITRAN2012 [23]. These air-broadened widths were carried forward from HITRAN2004 [24], where a
polynomial in |m| was fit to the measurements of Refs. [3,4,6]. The agreement between our measured air-
broadening coefficients and corresponding calculated values obtained using the EPG scaling law is within
±4% for most m values as can be seen in Table 3 and Figure 5 (B).
The air-shift coefficients are plotted in Figure 6 (A) as a function of m. Comparing these values
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with the published measurements by Loos et al. [10], and values from the HITRAN2016 [2] database, we
found that they are in agreement, and the differences are plotted vs. m in Figure 6 (B). We note that the
HITRAN2016 air-induced shift values for |m| ≤ 40 in the ν3 band are from Loos et al. [10], while the
shifts for higher |m| values are empirical estimates (based on the work of Toth [4]) carried forward from
HITRAN2012 [23] and earlier versions of that database. Figure 6(B) shows that the differences between
the present results and those of Loos et al. [10] are generally less than ±0.0005 cm-1
atm-1
, while the
disagreement between our values and the HITRAN2016 values is larger for |m| > 40. Similarly to the
widths, the shifts retrieved from our spectra using VP are only slightly different from those retrieved using
SDV. The error bars in Figure 6(A) indicate that the precision of our measured SDV pressure shift
coefficients is less for the weaker lines in both P - and R- branches.
The results of calculations for air-broadening and line mixing coefficients carried out with the
EPG scaling law are presented in Table 3. The calculation results are plotted in Figures 5(A) and 7. As
can be observed from these two figures, even though the EPG law is semi-empirical the results it provides
are mostly within about ±10% of the measured values, and this law could be considered for extrapolations
of broadening and of line mixing coefficients beyond the range of experimental results. In addition, line
mixing coefficients calculated by this method can be used in applications where experimental line mixing
coefficients are not available for the N2O transitions of interest.
An examination of Figure 7 shows that the calculated line mixing coefficients for P- and R-branch
transitions have similar patterns but of opposite sign and show a smooth m = 55. Where the intensity is the
highest, the sign of line mixing parameter changes due to the fact that intensity is transferred from weak to
strong absorption regions of the spectra. In addition, it is encouraging to note that both the line mixing
coefficients calculated with the EPG law and our retrieved line mixing coefficients agree well with the
experimental values of line mixing coefficients reported in Ref. [10].
4. Conclusions
In this study, we report accurate line-shape parameters of air-broadened N2O obtained from
retrievals using the quadratic SDV profile with an additional component to account for line mixing. Line
positions and intensities, air-broadened half-width coefficients, air-shift coefficients, and line mixing
coefficients using the Rosenkranz method are retrieved. These line shape parameters in the ν3 band are
reported for transitions up to |m| = 55.
Our comparison of line positions with published results and those listed in the HITRAN 2016 and
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GEISA 2015 databases show good agreement between the various sets. When we compared our
measured intensities with results from the HITRAN2016 and GEISA2015 databases, we were unable to find
systematic differences among the results. The observed differences are attributed to the fact that the line
intensity information stored in databases was obtained using the Voigt profile, whereas the present set of
intensities were obtained using the speed-dependent Voigt profile.
The air-broadened half-width coefficients are in good agreement with the values published by
Lacome et al. [3], Toth et al. [4], Nemtchinov et al. [6], and Loos et al. [10]. The air-broadening
coefficients obtained with the SDV model are slightly smaller than earlier published values [3,4,6] (~2%
percent), the majority of which were obtained using the Voigt profile. This observation is consistent with
results published by other groups (for example Ref. [25]). Indeed with very few exceptions, our air-
broadening and shift results agree best with those published by Loos et al. [10] where the authors also
used the SDV line shape model. In fact, we have extended the range of air-broadening and shift
coefficients obtained with the SDV model from the |m|≤40 of Ref. [10] to |m|≤55. At values of |m| above
50, there is more scatter in our results, in particular in the P-branch, that is attributed to the overlap with
transitions from other N2O bands and due to the fact that the transitions are much weaker at higher |m|.
The measured and calculated line mixing coefficients show very good agreement with the values
obtained by Loos et al. [10]. The data recorded for this study do not cover a wide range of temperatures,
and for this reason the temperature dependences of width and shift coefficients could not be determined.
A follow-up study involving several cold spectra of N2O and air mixtures is underway, and in the future
we expect to report our results for temperature dependences of line parameters.
Acknowledgements
The spectra used in this study were recorded with the assistance of Mike Dulick while he was at the the
McMath-Pierce Fourier transform spectrometer facility at the National Solar Observatory on Kitt Peak.
We are grateful to Dr. D. Chris Benner of the Department of Physics, College of William and Mary for
allowing us to use his Labfit software in our multispectrum analysis. The researchers at the University of
Lethbridge were funded by the Natural Sciences and Engineering Research Council of Canada and
Alberta Innovates Technology Futures (AITF) (R. Hashemi). The research at the College of William and
Mary, and NASA Langley Research center was supported by grants and cooperative agreements with the
National Aeronautics and Space Administration.
References
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1. WMO Global Ozone Research Monitoring Project 1986. Report No. 16, III, 835 (1985).
2. I E Gordon, L S Rothman, C Hill, R V Kochanov et al. J Quant Spectrosc Radiat Transf. 203, 3
(2017).
3. N Lacome, A Levy, G Guelachvili, Appl Opt. 23, 425 (1984).
4. R A Toth, J Quant Spectrosc Radiat Transf. 66, 285 (2000).
5. R A Toth, Applied Optics, 32, 7326 (1993).
6. V Nemtchinov, C Sun, P Varanasi, J Quant Spectrosc Radiat Transf. 83, 267 (2004).
7. A Vitcu, R Ciurylo, R Wehr, J R Drummond, A D May, J Mol Spectrosc. 226, 71 (2004).
8. L L Strow, A S Pine, J Chem Phys. 89, 1427 (1988).
9. M Margottin-Maclou, A Henry, J Chem Phys. 96, 1715 (1992).
10. J Loos, M Birk, G Wagner, J Quant Spectrosc Radiat Transf. 151, 300 (2015).
11. J M Hartmann, J P Bouanich, G Blanquet, J Walrand, D Bermejo, J L Domenech, and N
Lacome, J. Chem. Phys. 110, 1344 (1999).
12. W V Uber das, Sitzber, Bayr Akad. Mnchen. Ber. 603 (1912).
13. V M Devi, D C Benner, M A H Smith, A W Mantz, K Sung, L R Brown et al., J Quant
Spectrosc Radiat Transf. 113, 1013 (2012).
14. L R Brown, D C Benner, V M Devi, M A H Smith, R A Toth, J Mol Structure. 742, 111
(2005).
15. M A H Smith, C P Rinsland, V M Devi, D C Benner, Spectrochimica Acta. 48A, 1257 (1992).
16. D C Benner, C P Rinsland, V M Devi, M A H Smith, D Atkins, J Quant Spectrosc Radiat
Transf. 53, 705 (1995).
17. K Levenberg, Quart. Appl. Math. 2, 164 (1944).
18. D W Marquardt, J. Sot. Indust. Appl. Math. 11, 431 (1963).
19. A Predoi-Cross, A V Unni, H Heung, V M Devi, D C Benner, L R Brown, J Mol
Spectrosc. 246, 65 (2007).
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20. V P Kochanov, J Quant Spectrosc Radiat Transf. 189, 18 (2017).
21. J M Hartmann, C Boulet and D Robert, Elsevier Science, ISBN 978–0–444–52017–3 (2008).
22. N Jacquinet-Husson, R Armante, N A Scott, A Chédin et al. J Mol Spectrosc. 327, 31(2016).
23. L S Rothman, I E Gordon, Y Babikov, A Barbe et al. J Quant Spectrosc Radiat Transf.
130, 4 (2013).
24. L S Rothman, D Jacquemart, A Barbe, D C Benner et al. J Quant Spectrosc Radiat Transf.
96, 139 (2005).
25. A Predoi-Cross, F Rohart, J-P Bouanich, D Hurtmans, Can J Phys 87(5), 485 (2009).
List of Tables
Table 1. Experimental conditions of recorded spectra. VMR is the volume mixing ratio, P is the total
sample pressure in Torr and T is the temperature in K. The pathlength is 50 cm for all spectra.
Table 2. Measureda line positions in cm
-1, intensities in cm
-1/(molecule·cm
-2), air-broadened half-width
coefficients and air-shift coefficients of N2O in cm-1
atm-1
obtained using the speed-dependent Voigt
profile. A constant speed dependence value of 0.0895 has been used for each transition. The Einstein A
coefficients in s-1
are also reported.
Table 3. Measured air-broadened half-width coefficients (cm-1
atm-1
at 296 K) and line mixing parameters
(atm-1
) and corresponding calculated values obtained using the EPG scaling law.
List of Figures
Fig. 1. Experimental spectrum of the ν3 band of nitrous oxide recorded at P= 1.012 Torr and T=294.15
K. The path length of the absorption cell is L = 50 cm.
Fig. 2. Example of a fitted spectral interval of the ν3 band of nitrous oxide broadened by air (see Table 1).
Panel (A) shows the observed spectra, and Panel (B) shows the fit residuals obtained using the quadratic
speed dependent Voigt profile with a weak line mixing component.
Fig. 3. Measured line position differences with values in the HITRAN2016 [2] and GEISA2015 [22]
databases and with values reported by Nemtchinov et al. [6] and Loos et al. [10]. Note that the line
positions listed in Table 3 of Ref. [10] are from the 2012 edition of HITRAN [23]. The differences
have been obtained by subtracting our results from the values presented in the other lists. The average
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13
values are presented using dashed lines (see legend). Note that m = −J for the P -branch transitions,
m = J + 1 for the R-branch transitions, and J is the lower state rotational quantum number.
Fig. 4. (A) Measured line intensity percentage difference of present study (PS) compared with
HITRAN2016 and GEISA2015 databases ((Values in database-PS)×100/PS) and with the results of
Nemtchinov et al. (2004). The average values are shown with dashed lines. (B) Ratios between line
intensities in HITRAN2016 and GEISA2015 databases and from the study of Nemtchinov et al. (2004)
and the corresponding line intensities from the present study. The data points corresponding to P45,
P35 and R2 were not included.
Fig. 5. (A) Air- broadening coefficients for N2O transitions overlaid with published results by Toth et
al. [4], Lacome et al. [3], Nemtchinov et al. [6], Loos et al. [10] and parameters stored in the
HITRAN2016 [2] and GEISA2015 [22] databases. Lastly, the values for air-broadening coefficients
calculated using the EPG scaling law are overlaid on the same plot. (B) Percent differences between
our SDV air-broadening coefficients and previous studies, EPG calculations, database values, and
results obtained with the Voigt profile from our spectra ({Other study – PS(SDV)} × 100 / PS(SDV)).
Fig. 6. (A) Retrieved SDV air-induced pressure shift coefficients for N2O transitions of the ν3 band of
N2O overlaid with measurements by Loos et al. [10], values from the HITRAN2016 [2] database, and
results obtained from our spectra with the Voigt profile. (B) Differences (Other work – PS(SDV))
between our SDV air-shift coefficients and the other values shown in panel (A) .
Fig. 7. Line mixing coefficients for transitions in the ν3 band of N2O from the present study (both SDV
and Voigt profiles) plotted overlaid with the results from Ref. [10] and values calculated using the EPG
formalism.
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Fig. 1. Experimental spectrum of the ν3 band of nitrous oxide recorded at P= 1.012 Torr and T=294.15 K.
The path length of the absorption cell is L = 50 cm.
240x174mm (96 x 96 DPI)
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Fig. 2. Example of a fitted spectral interval of the ν3 band of nitrous oxide broadened by air (see Table 1). Panel (A) shows the observed spectra, and Panel (B) shows the fit residuals obtained using the quadratic
speed dependent Voigt profile with a weak line mixing component.
241x174mm (96 x 96 DPI)
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240x174mm (96 x 96 DPI)
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Fig. 3. Measured line position differences with values in the HITRAN2016 [2] and GEISA2015 [22] databases and with values reported by Nemtchinov et al. [6] and Loos et al. [10]. Note that the line positions listed in
Table 3 of Ref. [10] are from the 2012 edition of HITRAN [23]. The differences have been obtained by subtracting our results from the values presented in the other lists. The average values are presented using
dashed lines (see legend). Note that m = −J for the P -branch transitions, m = J + 1 for the R-branch transitions, and J is the lower state rotational quantum number.
240x174mm (96 x 96 DPI)
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Fig. 4. (A) Measured line intensity percentage difference of present study (PS) compared with HITRAN2016 and GEISA2015 databases ((Values in database-PS)×100/PS) and with the results of Nemtchinov et al.
(2004). The average values are shown with dashed lines. (B) Ratios between line intensities in HITRAN2016 and GEISA2015 databases and from the study of Nemtchinov et al. (2004) and the corresponding line
intensities from the present study. The data points
240x174mm (96 x 96 DPI)
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240x174mm (96 x 96 DPI)
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Fig. 5. (A) Air- broadening coefficients for N2O transitions overlaid with published results by Toth et al. [4], Lacome et al. [3], Nemtchinov et al. [6], Loos et al. [10] and parameters stored in the HITRAN2016 [2] and
GEISA2015 [22] databases. Lastly, the values for air-broadening coefficients calculated using the EPG
scaling law are overlaid on the same plot. (B) Percent differences between our SDV air-broadening coefficients and previous studies, EPG calculations, database values, and results obtained with the Voigt
profile from our spectra ({Other study – PS(SDV)} × 100 / PS(SDV)).
240x174mm (96 x 96 DPI)
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240x174mm (96 x 96 DPI)
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Fig. 6. (A) Retrieved SDV air-induced pressure shift coefficients for N2O transitions of the ν3 band of N2O overlaid with measurements by Loos et al. [10], values from the HITRAN2016 [2] database, and results
obtained from our spectra with the Voigt profile. (B) Differences (Other work – PS(SDV)) between our SDV
air-shift coefficients and the other values shown in panel (A).
240x174mm (96 x 96 DPI)
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240x174mm (96 x 96 DPI)
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Fig. 7. Line mixing coefficients for transitions in the ν3 band of N2O from the present study (both SDV and
Voigt profiles) plotted overlaid with the results from Ref. [10] and values calculated using the EPG formalism.
240x174mm (96 x 96 DPI)
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Table 1. Experimental conditions of recorded spectra. VMR is the volume mixing ratio, P is the
total sample pressure in Torr and T is the temperature in K. The pathlength is 50 cm for all
spectra.
Spectra Gas sample VMR P(Torr) T(K)
1 N2O 1.0000 1.012 241.15
2 N2O+air 0.0119 110.95 295.90
3 N2O+air 0.0113 204.90 295.65
4 N2O+air 0.0007 302.05 294.60
5 N2O+air 0.0006 503.55 294.15
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Table 2: Measureda line positions in cm
-1, intensities in cm
-1/(molecule·cm
-2), air-broadened half-width
coefficients and air-shift coefficients of N2O in cm-1
atm-1
obtained using the speed-dependent Voigt
profile. A constant speed dependence value of 0.0895 has been used for each transition.The Einstein A
coefficients in s-1
are also reported.
m Line positions
(cm-1
)
Intensities ×××× 1020
(cm-1
/(molecule·cm-2
))
Air
broadening
(cm-1
atm-1
)
Air shift
(cm-1
atm-1
)
Line mixing
(atm-1
)b
Speed
dependencec
A
(s-1
)
-54 2168.74147(4) 1.314(4) 0.07039(24) -0.00358(26) 0.00390(12) 0.0895(F) 102.727
-53 2169.9389(4) 1.598(3) 0.07075(19) -0.00366(23) 0.00477(12) 0.0895(F) 102.326
-52 2171.12972(4) 1.953(3) 0.06980(17) -0.00316(20) 0.00468(12) 0.0895(F) 102.833
-51 2172.31384(3) 2.341(3) 0.07024(17) -0.00356(19) 0.00462(11) 0.0895(F) 101.876
-50 2173.49129(3) 2.858(4) 0.07096(16) -0.00336(17) 0.00553(16) 0.0895(F) 103.273
-49 2174.66204(3) 3.420(4) 0.07006(16) -0.00262(18) 0.00387(17) 0.0895(F) 103.056
-48 2175.82619(4) 4.052(18) 0.07143(41) -0.0028(19) 0.00455(9) 0.0895(F) 102.2
-47 2176.98362(3) 4.784(7) 0.06995(16) -0.00329(17) 0.00498(12) 0.0895(F) 101.56
-46 2178.13426(3) 5.704(8) 0.07061(15) -0.00226(17) 0.0050(13) 0.0895(F) 102.361
-45 2179.27796(4) 8.187(18) 0.07022(17) -0.00120(18) 0.00461(12) 0.0895(F) 124.662
-44 2180.4156(3) 8.060(26) 0.07130(17) -0.00271(23) 0.00507(11) 0.0895(F) 104.695
-43 2181.54621(3) 9.257(12) 0.07099(12) -0.00208(14) 0.00459(10) 0.0895(F) 103.052
-42 2182.67027(3) 11.031(11) 0.07137(9) -0.00237(12) 0.00428(12) 0.0895(F) 105.645
-41 2183.78749(3) 12.586(13) 0.07143(10) -0.00255(12) 0.00449(9) 0.0895(F) 104.237
-40 2184.89802(3) 14.361(18) 0.07078(10) -0.00253(12) 0.00548(9) 0.0895(F) 103.343
-39 2186.00183(3) 16.452(15) 0.07134(8) -0.00242(12) 0.00529(9) 0.0895(F) 103.266
-38 2187.09881(3) 18.838(18) 0.07091(9) -0.00221(11) 0.00490(6) 0.0895(F) 103.745
-37 2188.18919(3) 21.392(18) 0.07104(8) -0.00206(10) 0.00553(7) 0.0895(F) 103.783
-36 2189.27272(3) 24.284(22) 0.07105(8) -0.00185(10) 0.00546(7) 0.0895(F) 104.363
-35 2190.34962(3) 27.347(25) 0.07163(8) -0.00224(9) 0.00488(6) 0.0895(F) 104.488
-34 2191.41987(5) 32.104(150) 0.07125(15) -0.00281(18) 0.00540(5) 0.0895(F) 109.735
-33 2192.48302(3) 34.048(58) 0.07177(10) -0.00227(11) 0.00492(10) 0.0895(F) 104.515
-32 2193.53965(3) 38.100(27) 0.07230(7) -0.00235(8) 0.00485(5) 0.0895(F) 105.573
-31 2194.58947(3) 42.096(30) 0.07266(7) -0.00196(8) 0.00512(6) 0.0895(F) 105.924
-30 2195.63287(3) 46.142(34) 0.07275(8) -0.00259(8) 0.00510(5) 0.0895(F) 105.835
-29 2196.66915(3) 50.243(35) 0.07280(7) -0.00224(8) 0.00468(5) 0.0895(F) 105.673
-28 2197.69871(3) 54.719(39) 0.07277(8) -0.00243(8) 0.00499(5) 0.0895(F) 106.136
-27 2198.72146(3) 58.993(47) 0.07316(9) -0.00250(8) 0.00498(5) 0.0895(F) 106.058
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-26 2199.73735(3) 63.187(54) 0.07349(10) -0.00237(9) 0.00393(5) 0.0895(F) 105.881
-25 2200.74653(4) 68.310(83) 0.07360(11) -0.00207(11) 0.00400(4) 0.0895(F) 107.267
-24 2201.74895(5) 73.980(230) 0.07325(22) -0.00255(15) 0.00399(5) 0.0895(F) 109.462
-23 2202.74459(4) 76.255(74) 0.07466(11) -0.00250(10) 0.00402(4) 0.0895(F) 107.000
-22 2203.73337(3) 80.199(74) 0.07533(10) -0.00253(9) 0.00409(5) 0.0895(F) 107.365
-21 2204.71534(3) 83.765(80) 0.07548(10) -0.00231(9) 0.00403(4) 0.0895(F) 107.620
-20 2205.69039(4) 87.045(86) 0.0762(11) -0.00215(10) 0.00399(4) 0.0895(F) 107.945
-19 2206.65883(3) 90.021(90) 0.07672(11) -0.00253(10) 0.00384(5) 0.0895(F) 108.576
-18 2207.62052(4) 92.035(96) 0.07722(12) -0.00284(10) 0.00413(4) 0.0895(F) 108.754
-17 2208.57511(4) 93.155(95) 0.07844(12) -0.00244(10) 0.00185(5) 0.0895(F) 108.561
-16 2209.52314(4) 94.274(100) 0.07903(12) -0.00307(11) -0.00221(5) 0.0895(F) 109.214
-15 2210.46409(4) 94.273(93) 0.07973(11) -0.00228(10) 0.00062(5) 0.0895(F) 109.516
-14 2211.39826(4) 93.620(90) 0.08071(11) -0.00219(10) -0.00076(5) 0.0895(F) 109.915
-13 2212.32567(4) 92.162(87) 0.08111(11) -0.00233(10) -0.00224(5) 0.0895(F) 110.529
-12 2213.24627(4) 89.607(82) 0.08189(11) -0.00202(10) -0.00487(5) 0.0895(F) 110.918
-11 2214.15989(4) 85.999(75) 0.08299(11) -0.00236(10) -0.00200(5) 0.0895(F) 111.087
-10 2215.06667(4) 81.756(73) 0.08398(11) -0.00191(11) -0.00270(5) 0.0895(F) 111.678
-9 2215.96655(8) 76.194(300) 0.08561(21) -0.00211(15) -0.00396(5) 0.0895(F) 111.778
-8 2216.85971(4) 71.076(77) 0.08640(12) -0.00231(12) -0.00509(5) 0.0895(F) 113.969
-7 2217.74596(4) 64.185(50) 0.08767(10) -0.00206(10) -0.00736(5) 0.0895(F) 115.087
-6 2218.62529(3) 56.581(43) 0.08887(9) -0.00211(9) -0.01032(6) 0.0895(F) 116.615
-5 2219.49774(3) 48.309(31) 0.09019(8) -0.00189(9) -0.01145(7) 0.0895(F) 118.894
-4 2220.36329(3) 39.421(27) 0.09113(8) -0.00160(10) -0.01352(6) 0.0895(F) 122.236
-3 2221.22203(3) 30.136(54) 0.09234(11) -0.00127(15) -0.01262(7) 0.0895(F) 128.879
-2 2222.07381(4) 20.494(58) 0.09562(16) -0.00121(20) -0.01738(7) 0.0895(F) 144.417
-1 2222.91871(3) 10.213(12) 0.10026(15) -0.00139(18) -0.01836(9) 0.0895(F) 214.251
1 2224.58788(3) 10.302(11) 0.10053(15) -0.00177(16) 0.01925(11) 0.0895(F) 71.861
2 2225.41215(3) 20.581(18) 0.09544(10) -0.00148(13) 0.01921(7) 0.0895(F) 86.546
3 2226.22968(6) 34.302(170) 0.09259(27) 0.00020(33) 0.01626(7) 0.0895(F) 103.952
4 2227.03986(3) 39.974(36) 0.09157(10) -0.00143(11) 0.01412(6) 0.0895(F) 95.451
5 2227.84333(3) 49.341(34) 0.08975(8) -0.00145(9) 0.01204(6) 0.0895(F) 98.045
6 2228.63983(3) 58.262(48) 0.08936(10) -0.00132(9) 0.01103(6) 0.0895(F) 100.054
7 2229.42949(3) 66.061(55) 0.08800(11) -0.0017(10) 0.01043(5) 0.0895(F) 100.821
8 2230.212(5) 76.312(110) 0.08539(13) -0.00078(15) 0.00878(5) 0.0895(F) 105.773
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9 2230.98792(3) 79.555(71) 0.08497(12) -0.00137(10) 0.00647(5) 0.0895(F) 102.06
10 2231.75673(3) 85.537(73) 0.08404(11) -0.00140(9) 0.00558(5) 0.0895(F) 103.051
11 2232.5185(3) 90.633(82) 0.08349(12) -0.00133(10) 0.00429(5) 0.0895(F) 103.887
12 2233.27335(3) 94.523(110) 0.08220(14) -0.00127(11) 0.00394(5) 0.0895(F) 104.285
13 2234.02148(4) 97.398(130) 0.08082(19) -0.00176(16) 0.00346(5) 0.0895(F) 104.574
14 2234.76242(4) 99.054(140) 0.07998(19) -0.00173(12) 0.00192(7) 0.0895(F) 104.489
15 2235.49646(4) 100.49(140) 0.07931(17) -0.00163(12) 0.00126(7) 0.0895(F) 105.023
16 2236.22352(4) 101.8(160) 0.07937(21) -0.00154(12) 0.00055(7) 0.0895(F) 106.363
17 2236.94367(4) 100.66(140) 0.07804(19) -0.00177(11) -0.00184(6) 0.0895(F) 105.905
18 2237.65679(3) 99.412(130) 0.07703(16) -0.00181(10) -0.00116(6) 0.0895(F) 106.074
19 2238.36292(3) 98.056(140) 0.07616(18) -0.00177(11) -0.00186(6) 0.0895(F) 106.902
20 2239.06205(3) 94.403(110) 0.07637(14) -0.00192(10) -0.00285(6) 0.0895(F) 105.859
21 2239.75424(3) 91.868(100) 0.07579(13) -0.00159(9) -0.00413(6) 0.0895(F) 106.592
22 2240.43952(3) 88.529(92) 0.07544(12) -0.00220(9) -0.00398(6) 0.0895(F) 106.96
23 2241.11777(3) 84.439(86) 0.07480(11) -0.00197(9) -0.00494(5) 0.0895(F) 106.921
24 2241.78890(3) 80.336(79) 0.07430(11) -0.00170(9) -0.00639(6) 0.0895(F) 107.175
25 2242.45307(3) 76.315(77) 0.07390(11) -0.00183(9) -0.00608(6) 0.0895(F) 107.995
26 2243.11032(2) 71.635(56) 0.07364(8) -0.00198(8) -0.00677(5) 0.0895(F) 108.018
27 2243.76050(2) 66.542(50) 0.07339(8) -0.00200(8) -0.00796(5) 0.0895(F) 107.582
28 2244.40378(2) 62.111(44) 0.07312(7) -0.00199(8) -0.00720(5) 0.0895(F) 108.133
29 2245.03995(2) 57.317(39) 0.07314(7) -0.00206(8) -0.00789(5) 0.0895(F) 108.181
30 2245.66907(2) 52.745(35) 0.07289(6) -0.00216(8) -0.00927(4) 0.0895(F) 108.368
31 2246.29122(2) 48.228(31) 0.07232(6) -0.00207(8) -0.00922(4) 0.0895(F) 108.458
32 2246.90634(2) 43.785(28) 0.07215(6) -0.00214(8) -0.0101(5) 0.0895(F) 108.382
33 2247.51438(2) 39.755(25) 0.07229(6) -0.00207(8) -0.01001(5) 0.0895(F) 108.789
34 2248.11544(2) 35.829(22) 0.07198(6) -0.00205(8) -0.00960(5) 0.0895(F) 108.94
35 2248.70947(2) 32.175(20) 0.07162(6) -0.00239(8) -0.01267(5) 0.0895(F) 109.203
36 2249.29644(2) 28.700(18) 0.07154(6) -0.00231(8) -0.01116(6) 0.0895(F) 109.329
37 2249.87636(2) 25.350(16) 0.07130(6) -0.00229(8) -0.01292(6) 0.0895(F) 108.872
38 2250.4492(2) 22.507(15) 0.07127(6) -0.00244(9) -0.01199(6) 0.0895(F) 109.507
39 2251.01499(2) 19.738(14) 0.07129(6) -0.00212(9) -0.01274(7) 0.0895(F) 109.343
40 2251.57371(2) 17.264(13) 0.07130(7) -0.00223(10) -0.01341(9) 0.0895(F) 109.332
41 2252.12542(2) 15.056(12) 0.07097(7) -0.0024(10) -0.01367(7) 0.0895(F) 109.599
42 2252.67012(2) 13.063(11) 0.07084(8) -0.00234(11) -0.01419(8) 0.0895(F) 109.697
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43 2253.20761(2) 11.273(10) 0.07083(8) -0.00205(11) -0.01452(8) 0.0895(F) 109.814
44 2253.73818(2) 9.693(9) 0.07087(9) -0.00281(12) -0.01512(10) 0.0895(F) 109.941
45 2254.26158(2) 8.336(8) 0.07065(10) -0.0024(13) -0.01547(11) 0.0895(F) 110.671
46 2254.77800(2) 7.052(8) 0.07087(11) -0.00329(13) -0.01619(14) 0.0895(F) 110.056
47 2255.28725(3) 6.008(7) 0.07066(12) -0.00287(14) -0.01654(12) 0.0895(F) 110.692
48 2255.78941(3) 5.056(6) 0.07058(13) -0.00316(14) -0.01691(11) 0.0895(F) 110.529
49 2256.28451(3) 4.272(5) 0.07069(13) -0.00358(15) -0.01758(18) 0.0895(F) 111.26
50 2256.77257(3) 3.558(4) 0.07089(13) -0.00402(16) -0.01869(11) 0.0895(F) 110.884
51 2257.25346(3) 2.974(3) 0.07023(13) -0.00374(16) -0.01827(11) 0.0895(F) 111.403
52 2257.72739(3) 2.461(3) 0.07055(14) -0.00459(17) -0.0185(24) 0.0895(F) 111.348
53 2258.19396(3) 2.049(2) 0.07035(14) -0.00440(19) -0.01857(15) 0.0895(F) 112.362
54 2258.65373(4) 1.682(2) 0.07077(15) -0.00510(20) -0.01935(18) 0.0895(F) 112.425
55 2259.10613(4) 1.383(2) 0.06958(16) -0.00515(22) -0.01816(41) 0.0895(F) 113.026
56 2259.55158(5) 1.126(2) 0.06985(19) -0.00513(25) -0.01829(27) 0.0895(F) 113.153
a All parameters correspond to T=296 K.
b First order line mixing coefficient using the Rosenkranz approximation.
c unitless.
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Table 3. Measured air-broadened half-width coefficients (cm-1atm
-1 at 296 K) and line mixing parameters
(atm-1) and corresponding calculated values obtained using the EPG scaling law.
m
Air broadening Air line mixing
Experimental
EPG
calculation
%
difference Experimental
EPG
calculation
-50 0.07096 0.06980? 1.63 0.0055 0.0077
-49 0.07006 0.06977 0.41 0.0039 0.0076
-48 0.07143 0.06974 2.37 0.0046 0.0076
-47 0.06995 0.06971 0.34 0.0050 0.0076
-46 0.07061 0.06969 1.30 0.0050 0.0075
-45 0.07022 0.06967 0.78 0.0046 0.0075
-44 0.07130 0.06966 2.30 0.0051 0.0075
-43 0.07099 0.06965 1.89 0.0046 0.0074
-42 0.07137 0.06965 2.41 0.0043 0.0074
-41 0.07143 0.06966 2.48 0.0045 0.0073
-40 0.07078 0.06968 1.55 0.0055 0.0072
-39 0.07134 0.06970 2.30 0.0053 0.0071
-38 0.07091 0.06973 1.66 0.0049 0.0071
-37 0.07104 0.06978 1.77 0.0055 0.0070
-36 0.07105 0.06983 1.72 0.0055 0.0069
-35 0.07163 0.06990 2.42 0.0049 0.0068
-34 0.07125 0.06998 1.78 0.0054 0.0067
-33 0.07177 0.07007 2.37 0.0049 0.0066
-32 0.07230 0.07018 2.93 0.0049 0.0065
-31 0.07266 0.07031 3.23 0.0051 0.0063
-30 0.07275 0.07046 3.15 0.0051 0.0061
-29 0.07280 0.07062 2.99 0.0047 0.006
-28 0.07277 0.07081 2.69 0.0050 0.0058
-27 0.07316 0.07102 2.93 0.0050 0.0056
-26 0.07349 0.07126 3.03 0.0039 0.0053
-25 0.07360 0.07153 2.81 0.0040 0.0051
-24 0.07325 0.07183 1.94 0.0040 0.0049
-23 0.07466 0.07216 3.35 0.0040 0.0046
-22 0.07533 0.07254 3.70 0.0041 0.0043
-21 0.07548 0.07295 3.35 0.0040 0.0039
-20 0.07620 0.07341 3.66 0.0040 0.0036
-19 0.07672 0.07393 3.64 0.0038 0.0032
-18 0.07722 0.07450 3.52 0.0041 0.0027
-17 0.07844 0.07513 4.22 0.0019 0.0022
-16 0.07903 0.07584 4.04 -0.0022 0.0016
-15 0.07973 0.07663 3.89 0.0006 0.0009
-14 0.08071 0.07750 3.98 -0.0008 0.0002
-13 0.08111 0.07848 3.24 -0.0022 -0.0006
-12 0.08189 0.07956 2.85 -0.0049 -0.0016
-11 0.08299 0.08078 2.66 -0.0020 -0.0026
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-10 0.08398 0.08214 2.19 -0.0027 -0.0039
-9 0.08561 0.08367 2.27 -0.0040 -0.0054
-8 0.08640 0.08539 1.17 -0.0051 -0.0072
-7 0.08767 0.08733 0.39 -0.0074 -0.0095
-6 0.08887 0.08952 -0.73 -0.0103 -0.0123
-5 0.09019 0.09199 -2.00 -0.0115 -0.0161
-4 0.09113 0.09478 -4.01 -0.0135 -0.0211
-3 0.09234 0.09785 -5.97 -0.0126 -0.0287
-2 0.09562 0.10094 -5.56 -0.0174 -0.0419
-1 0.10026 0.10213 -1.87 -0.0184 -0.0737
1 0.10053 0.10432 -3.77 0.0193 0.0500
2 0.09544 0.10213 -7.01 0.0192 0.0292
3 0.09259 0.10094 -9.02 0.0163 0.0235
4 0.09157 0.09785 -6.86 0.0141 0.0193
5 0.08975 0.09478 -5.60 0.0120 0.0161
6 0.08936 0.09199 -2.94 0.0110 0.0133
7 0.08800 0.08952 -1.73 0.0104 0.0111
8 0.08539 0.08733 -2.27 0.0088 0.0092
9 0.08497 0.08539 -0.49 0.0065 0.0075
10 0.08404 0.08367 0.44 0.0056 0.0060
11 0.08349 0.08214 1.62 0.0043 0.0047
12 0.08220 0.08078 1.73 0.0039 0.0036
13 0.08082 0.07956 1.56 0.0035 0.0025
14 0.07998 0.07848 1.88 0.0019 0.0015
15 0.07931 0.07750 2.28 0.0013 0.0005
16 0.07937 0.07663 3.45 0.0006 -0.0003
17 0.07804 0.07584 2.82 -0.0018 -0.0011
18 0.07703 0.07513 2.47 -0.0012 -0.0019
19 0.07616 0.07450 2.18 -0.0019 -0.0026
20 0.07637 0.07393 3.19 -0.0029 -0.0033
21 0.07579 0.07341 3.14 -0.0041 -0.0039
22 0.07544 0.07295 3.30 -0.0040 -0.0046
23 0.07480 0.07254 3.02 -0.0049 -0.0051
24 0.07430 0.07216 2.88 -0.0064 -0.0057
25 0.07390 0.07183 2.80 -0.0061 -0.0062
26 0.07364 0.07153 2.87 -0.0068 -0.0067
27 0.07339 0.07126 2.90 -0.0080 -0.0072
28 0.07312 0.07102 2.87 -0.0072 -0.0077
29 0.07314 0.07081 3.19 -0.0079 -0.0082
30 0.07289 0.07062 3.11 -0.0093 -0.0087
31 0.07232 0.07046 2.57 -0.0092 -0.0092
32 0.07215 0.07031 2.55 -0.0101 -0.0096
33 0.07229 0.07018 2.92 -0.0100 -0.0101
34 0.07198 0.07007 2.65 -0.0096 -0.0105
35 0.07162 0.06998 2.29 -0.0127 -0.0109
36 0.07154 0.06990 2.29 -0.0112 -0.0113
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37 0.07130? 0.06983 2.06 -0.0129 -0.0118
38 0.07127 0.06978 2.09 -0.0120 -0.0122
39 0.07129 0.06973 2.19 -0.0127 -0.0126
40 0.07130 0.06970 2.24 -0.0134 -0.0130
41 0.07097 0.06968 1.82 -0.0137 -0.0134
42 0.07084 0.06966 1.67 -0.0142 -0.0138
43 0.07083 0.06965 1.67 -0.0145 -0.0143
44 0.07087 0.06965 1.72 -0.0151 -0.0147
45 0.07065 0.06966 1.40 -0.0155 -0.0151
46 0.07087 0.06967 1.69 -0.0162 -0.0156
47 0.07066 0.06969 1.37 -0.0165 -0.0161
48 0.07058 0.06971 1.23 -0.0169 -0.0166
49 0.07069 0.06974 1.34 -0.0176 -0.0171
50 0.07089 0.06977 1.58 -0.0187 -0.0176
51 0.07023 0.06980 0.61 -0.0183 -0.0184
52 0.07055 0.06983 1.02 -0.0185 -0.0192
53 0.07035 0.06987 0.68 -0.0186 -0.0204
54 0.07077 0.06991 1.22 -0.0194 -0.0219
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