rotationally-resolved high-resolution laser spectroscopy of the b 2 e’ – x 2 a 2 ’ transition...
TRANSCRIPT
Rotationally-resolved high-resolution laser spectroscopyof the B 2E’ – X 2A2’ transition of 14NO3 radical
69th International Symposium on Molecular Spectroscopy@ Champaign-Urbana, Illinois, The United States
2014 / June / 16th
MI13
Shunji Kasahara1, Kohei Tada1†, Takashi Ishiwata2, and Eizi Hirota3
1 Kobe University, Japan;2 Hiroshima City University, Japan;
3 The Graduate University for Advanced Studies, Japan;† Research Fellow of Japan Society for the Promotion of Science.
Introduction
D3h
2NO2
HNO3 + R etc.
NO2 + O
NO + O2
+ NO+ RH
NO3
+ hν
+ hν
Wavenumber / 1000 cm-1
20
15
10
5
0
NO2 + O NO3 NO + O2
O2 (b 1Σg+)
O2 (a 1Δg)
O2 (X 3Σg-)
B 2E’
A 2E’’
X 2A2’
Vibronic Band~ 16000 cm-1 (~ 625 nm)
0-0 band ~ 15100 cm-1 (~ 662 nm)
B - X 遷移
K. Mikhaylichenko et al., J. Chem. Phys., 105, 6807 (1996)
reaction coordinate
NO2 + O3 → NO3 + O2
N2O5 ⇄ NO3 + NO2
B 2E’ : … (4e’)3 (1e’’)4 (1a2)2 ~ 15000 cm-1
A 2E’’ : … (4e’)4 (1e’’)3 (1a2)2 ~ 7000 cm-1
X 2A2’ : … (4e’)4 (1e’’)4 (1a2)1 0 cm-1
662 nmAbsorption spectrum of 14NO3 (Visible)
J. Chem. Soc. Faraday 1176, 785 (1980).
⑤ LIF and Absorption spectra of 14NO3 B-X transition
Absorption spectrum of 14NO3 (Visible)
J. Chem. Soc. Faraday 1176, 785 (1980).
15000 15200 15400 15600 15800 16000 16200 16400 Wavenumber / cm-1
N2O5 → NO3 + NO2
M. Fukushima et al., 67th Int. Symp. Mol. Spectrosc., TI06 (2012)
Resolution : 0.2 cm-1
14NO3 B 2E’-X 2A2’ transition
15000 15200 15400 15600 15800 16000 16200 16400 Wavenumber / cm-1
15000 15200 15400 15600 15800 16000 16200 16400 Wavenumber / cm-1
LIF spectra of 14NO3 and 14NO2
N2O5 → NO3 + NO2
R. E. Smalley et al., J. Chem. Phys., 63, 4977 (1975)
Vibronic band0 - 0 band
M. Fukushima et al., 67th Int. Symp. Mol. Spectrosc., TI06 (2012)
NO2
Resolution : 0.2 cm-1
INTENSITY×5
?
14NO2 A 2B2-X 2A1 transition (Imax at 16849.8 cm-1)
Resolution : 0.0007 cm-1
14NO3 B 2E’-X 2A2’ transition
D
Exprimental setup
Absolute wavenumber mesurement system (Accuracy : 0.0001 cm-1)
Etalon
Liq.N2
Pump Pump
Pulsed Nozzle
Skimmer(ϕ= 2 mm)
Filter
N2O5 → NO3 + NO2 Slit(2 mm)
PBS
Molecular Beam (Typical linewidth : 0.0007 cm-1)
N2O5 + ArComputer
532 nm around 660 or 625 nm
Single mode laser ( Γ = 0.00003 cm-1 )PD
BS : Beam splitterPBS : Polarization beam splitterEOM : Electro-optic modulatorPD : Photo diodePMT : Photomultiplier tube
BS
EOM
I2 Cell
Heater 300 ℃NO2 + He
Ring DyeLaser
Nd:YVO4
Laser
Mirror Heater off
Photon Counter
PMT
~ 150 strong (> 15% of max) lines and more than 3000 weak (< 15% of max) lines were observed. ← too many!
The rotational assignment was very difficult.
(1) Combination difference
→ 0.0248 cm-1 line pairs
(2) Zeeman effect
→ Unambiguous Assignment
High-resolution LIF spectrum 14NO3 B-X 0-0 band at 662 nm
0.1 cm-1
15100.15 15100.20 15100.25
Wavenumber / cm-1
0.0248 cm-1
σ-pump (H⊥E) ΔMJ = ±1 π-pump (H // E) ΔMJ = 0
15100.20 15100.25
0 G
42 G
71 G
102 G
125 G
163 G
188 G
223 G
245 G
280 G
303 G
335 G
360 G
Wavenumber / cm-1
15100.20 15100.25
0 G
42 G
71 G
102 G
125 G
163 G
188 G
223 G
245 G
280 G
303 G
335 G
360 G
Wavenumber / cm-1
0.0246 cm-1 0.0246 cm-1
Zeeman effect around 15100.2 cm-1
40 G
70 G
100 G
160 G
190 G
220 G
305 G
40 G
70 G
100 G
160 G
190 G
220 G
305 G
σ-pump: ΔMJ = ±1
π-pump: ΔMJ = 0
(σ:4+6/π:2+3) pair
Symmetry-adopted basis setsThe X 2A2’ state:
The B 2E’ state:
JJ
J
MkJSN
kNMkJS
N
kN
FMNJSkN
,,,22
1,,,
22
1
,,,,,
21
21
21
21
21
21
121
21
JJ
J
MkJSN
kNMkJS
N
kN
FMNJSkN
,,,2
,,,2
,,,,,
21
21
21
21
21
21
221
21
JPJ
J
J
MPJSMPJS
EMSPJ
,,,1)(,,,12
1
',,,,,
21
21
21
21
2/32
21
JPJ
J
J
MPJSMPJS
EMSPJ
,,,1)(,,,12
1
',,,,,
21
211
21
21
2/12
21
Hund’s case (b) basis
Hund’s case (a) basis
The X 2A2’ state: HZ = gS μB H·S
The B 2E’ state: HZ = gS μB H·S + gL μB H·Leff
)12)(1(1
')()12)(1'2(
1
'
')(
0
1
'
')(''''
'''
'''''
SSSS
q
SgdgJJ
P
J
qP
J
M
J
M
JHJPMHMPJ
SSPPeL
PJ
JJq
MJMMBJZJ
J
JJ
ζ
JJ
JNSMJKKNNMMBSJZJ
M
J
M
JN
S
J
J
SSSSJJ
HgNKSJMHMJSKN J
JJ
0
1
'
'
1
')12)(1()12)(1'2(
)(''''' 1'''''
Refs: Endo et al., J. Chem. Phys., 81, 122 (1984)
Hirota, High-Resolution Spectroscopy of Transient Molecules, Springer (1985)
μB (= 4.6686×10-5 cm-1 G-1): Bohr magneton, gS: the electron spin g factor,
gL: the electron orbital g factor, and ζed: the effective value of <Λ|Lz|Λ>.
Zeeman Hamiltonians and matrix elements
0 100 200 300 400
15100.18
15100.20
15100.22
15100.24
Transition Energy / cm-1
Magnetic Field / Gauss
R(+0.5)
P(+0.5)
R(-1.5)RR
(-0.5)(+0.5)
P (-0.5)P(+0.5)
P(+1.5)
R(-0.5)
P(-0.5)
(σ:4+6/π:2+3) pair Zeeman splitting: transition to (2E’3/2, J = 1.5)
J = 1.5 ← 1.5
J = 1.5 ← 0.5
At 300 G
+ 0.5+ 1.5
– 0.5– 1.5
– 0.5+ 0.5
+ 1.5
+ 0.5– 0.5– 1.5
MJ
σ-pumpΔMJ = ±1
gS = 2.0215(4)
gS = 2.103(6)gLζed = – 0.138(11)
0 200 400 600
0.88
0.90
0.92
0.94
0.96
+ 0.5– 0.5
+ 1.5
+ 0.5– 0.5– 1.5
+ 1.5
+ 0.5– 0.5– 1.5
MJ
Magnetic field / G
Term energy / cm-1
J’ = 1.5
J” = 0.5
J” = 1.5
0 200 400 60015101.10
15101.12
15101.14
15101.16
15101.18
15101.20
0 100 200 300 400
15100.18
15100.20
15100.22
15100.24
Transition Energy / cm-1
Magnetic Field / Gauss
R(+0.5)
P(+0.5)
R(-1.5)RR
(-0.5)(+0.5)
P (-0.5)P(+0.5)
P(+1.5)
R(-0.5)
P(-0.5)
0 100 200 300 400
15100.18
15100.20
15100.22
15100.24
Transition Energy / cm-1
Magnetic Field / Gauss
R(+0.5)
P (+0.5)
R(-1.5)RR
(-0.5)(+0.5)
P (-0.5)P (+0.5)
P (+1.5)
R(-0.5)
P (-0.5)
ΔMJ (MJ”)
1510
0.20
1510
0.250 G
42 G
71 G
102
G
125
G
163
G
188
G
223
G
245
G
280
G
303
G
335
G
360
G
Wav
enum
ber
/ cm
-1
σ-pump (H⊥E) ΔMJ = ±1 π-pump (H // E)
ΔMJ = 0
Zeeman effect around 15130.75 cm-1
15130.75 15130.80
0 G
71 G
125 G
Wavenumber / cm-1
188 G
245 G
303 G
360 G
70 G
360 G
0.0246 cm-1
15130.75 15130.80
0 G
71 G
125 G
Wavenumber / cm-1
188 G
245 G
303 G
360 G
70 G
305 G
190 G
0.0246 cm-1
σ-pump: ΔMJ = ±1
π-pump: ΔMJ = 0
(σ:2+3/π:1+2) pair
σ-pump (H⊥E)ΔMJ=±1
Energy / cm-1
J’’=1.5
J’’=0.5
J’=0.5
MJ
+ 0.5
‐0.5
+ 0.5
‐0.5
+ 0.5
‐0.5
+ 1.5
‐1.5
Magnetic field / Gauss0 100 200 300 400
0.88
0.9
0.92
0.94
15131.66
15131.68
15131.7B 2E’1/2
X 2A2’(K’’=0 , N’’=1)
0 100 200 300 40015130.72
15130.74
15130.76
15130.78
15130.8σ-pump (H⊥E)
Wav
enu
mb
er /
cm-1
15130.7
15130.72
15130.74
15130.76
15130.78
15130.8
Wav
enu
mb
er /
cm-1
Magnetic field / Gauss
70 Gauss
15130.80 15131.70
The determined g-factors: lower: gS = 2.0215 (fixed) upper: gS = 1.892(26) gLζed = 0.214(51)
(σ:2+3/π:1+2) pair Zeeman splitting: transition to (2E’1/2, J = 0.5)
0 100 200 300 40015131.66
15131.67
15131.68
15131.69
Magnetic field / Gauss
En
ergy
/ c
m-1
σ-pump : ●
π-pump : ●
Calc : ―
MJ =‐0.5
MJ = +0.5
Perturbation ?
2E’3/2
2E’1/2
2A2’ (K” = 0, N” = 1)
J’ = 1.5
J’ = 1.5
J’ = 0.5
J” = 0.5J” = 1.5
0.0246cm-1
QRR Q
Q P
2E’3/2 ← 2A2’ : 7 transitions
Assigned line pairs from the Zeeman splittings
σ-pump: ΔMJ = ±1
π-pump: ΔMJ = 0
σ-pump: ΔMJ = ±1
π-pump: ΔMJ = 0
2E’1/2 ← 2A2’ : 15 transitions
15000 15200 15400 15600 15800 16000 16200 16400 Wavenumber / cm-1
15000 15200 15400 15600 15800 16000 16200 16400 Wavenumber / cm-1
N2O5 → NO3 + NO2
R. E. Smalley et al., J. Chem. Phys., 63, 4977 (1975)
M. Fukushima et al., 67th Int. Symp. Mol. Spectrosc., TI06 (2012)
NO2
⑤
Resolution : 0.2 cm-1
INTENSITY×5
0 + 950 cm-1 band :ν1
LIF spectra of 14NO3 and 14NO2
How about the vibronic bands?
NO2
N2O5 → NO3 + NO2
High-resolution LIF spectra 14NO3 0 + 950 cm-1 band and 14NO2
NO2
R (2)
R (0)
R (4)P (2)
0.2 cm-1 Resolution : 0.0007 cm-1
N2O5 → NO3 + NO2
NO2
Small signal, large background → difficult to analyze
NO3 signal Resolution : 0.0007 cm-1
High-resolution LIF spectra 14NO3 0 + 950 cm-1 band and 14NO2
15000 15200 15400 15600 15800 16000 16200 16400 Wavenumber / cm-1
15000 15200 15400 15600 15800 16000 16200 16400 Wavenumber / cm-1
NO2
N2O5 → NO3 + NO2
R. E. Smalley et al., J. Chem. Phys., 63, 4977 (1975)
0 + 770 cm-1 band : 2ν4
M. Fukushima et al., 67th Int. Symp. Mol. Spectrosc., TI06 (2012)
Resolution : 0.2 cm-1
INTENSITY×5
LIF spectra of 14NO3 and 14NO2
N2O5 → NO3 + NO2
NO2
0.2 cm-1Resolution : 0.0007 cm-1
High-resolution LIF spectra 14NO3 0 + 770 cm-1 band and 14NO2
N2O5 → NO3 + NO2
0.0246 cm-1
High-resolution LIF spectra 14NO3 0 + 770 cm-1 band and 14NO2 Resolution : 0.0007 cm-1
Large signal, small background, compared with 0 + 950 cm-1 band
0 G
12 G
25 G
37 G
50 G
62 G
J’ = 1.5
MJ
+ 1.5
+ 0.5
- 0.5
- 1.5
- 0.5
+ 0.5
+ 0.5
- 0.5
- 1.5
J” = 0.5
+ 1.5
π - pump (H // E), ΔMJ = 0
Zeeman Splitting at 15872.42 cm-1 line pair
J” = 1.5
0.0246 cm-1
0.0246 cm-1
N2O5 → NO3 + NO2
0.0246 cm-1
R (0.5) Q (1.5)
High-resolution LIF spectra 14NO3 0 + 770 cm-1 band and 14NO2 Resolution : 0.0007 cm-1
2E’3/2
2E’1/2
X 2A2’ (ʋ”=0, K” = 0, N” = 1)
J’ = 1.5
J’ = 1.5
J’ = 0.5
J” = 0.5J” = 1.5
0.0246cm-1
QRR Q
Q P
Summary
We have observed high-resolution fluorescence excitation spectra of 14NO3 B-X transition.
(1) 0-0 band [15070 – 15145 cm-1]
(2) 0+770 cm-1 band [15872 – 15874 cm-1] *
(3) 0+950 cm-1 band [16048– 16055 cm-1] * (* Not full region.)
Rotational assignment is difficult except the transitions from the X 2A2’ (K” = 0, N” = 1) levels. (0.0248 cm-1 pairs)
Unambiguous assignment of these 0.0248 cm-1 pairs is completed from the observed Zeeman splittings.
How about 15NO3?
MI14
Acknowledgement
Prof. Masaru Fukushima (Hiroshima City University) for his LIF spectrum of 15NO3.
Ms. Kanon Teramoto and Mr. Tsuyoshi Takashino (Undergraduate students, Kobe University) for their help.
Thank you for your attention!
Prof. Masaaki Baba (Kyoto University) for experimental setup at early stage.
How about 15NO3?
MI14
Electronic states of NO3
B 2E’
A 2E”
X 2A2’
~ 15100 cm-1
(~ 662 nm)
~ 7000 cm-1
(~ 1430 nm)
E”
E’
A2’
A2” LUMO
SOMO
NO3 …Planer triangle ⇒ D3h
Radical Doublet⇒
(Gaussian03, RHF/6-31g)
Vibrational Assignment
15000 15400 15800 16200 Wavenumber / cm-1
0 + 950 cm-1 bandM. Fukushima et al., 67th Int. Symp. Mol. Spectrosc., TI06 (2012)
振動モー
ド
既約表現
遷移波数 (cm-1)
X[1] [2] A[3] B
ν1 a1’ 1060 780 950
ν2 a2” 762 710
ν3 e’ 1480 (?) 1435
ν4 e’ 380 530 ~ 385
2ν4
ν1
0 + 770 cm-1 band
[1] T. Ishiwata et al., J. Phys. Chem., 87, 1349 (1983)[2] R. R. Friedl et al., J. Phys. Chem., 91, 2721 (1987)[3] T. J. Codd et al., 68th Int. Symp. Mol. Spectrosc., WJ05 (2013)
Normal Mode of NO3
+ - -
- ν2
A2”
ν1
A1’
ν3a
E’
ν3b
ν4a
E’
ν4b
E’ ν = E’
a1’, a2’, e’
B state
Vibrational level
Vibroniclevel
0 - 0 band
Complicated structure of the 662 nm band
Vib. mode FrequencyAnharmonic
constant
ν1 (a1’)
ν2 (a2”)
ν3 (e’)
ν4 (e’)
772.73
713.59
1688.12
511.20
– 4.603
– 10.268
0
+ 4.785
[Codd et al., 67th OSU meeting, TI01 (2012)]
The A state vibrational frequencies in cm-1
X 2A2’
A 2E”
B 2E’ {
15070 – 15145 cm-1 region: 10 ~ 15 E’-type levels
Complicated structure of the 662 nm band:(mainly) vibronic interaction with dark A state??
7060 cm-1
E” × A2” = E’
15100 cm-1
B 2E’ : Hund’s coupling case(a)
J RP
S
LΛΣ
z(c)
x(a)=y(b)
K NJ
R
L
S
z(c)
x(a)=y(b)
X 2A2’(v=0) : Hund’s coupling case(b)
good quantum number :
Λ, S, Σ, J, P, MJ , K
good quantum number :
N, K, S, J, MJ
Hund’s Couplig Case