Some New Emission Bands of Molecular OxygenS. J. Arnold, E. A. Ogryzlo, and H. Witzke Citation: The Journal of Chemical Physics 40, 1769 (1964); doi: 10.1063/1.1725394 View online: http://dx.doi.org/10.1063/1.1725394 View Table of Contents: http://scitation.aip.org/content/aip/journal/jcp/40/6?ver=pdfcov Published by the AIP Publishing Articles you may be interested in New emission spectra from oxygen Appl. Phys. Lett. 55, 2707 (1989); 10.1063/1.101931 The visible emissions of molecular oxygen in rare gas solids J. Chem. Phys. 65, 3948 (1976); 10.1063/1.432888 New Absorption Spectra of Atomic and Molecular Oxygen in the Vacuum Ultraviolet. I. Rydberg Seriesfrom O I Ground State and New Excited O2 Bands J. Chem. Phys. 46, 2213 (1967); 10.1063/1.1841026 Electronic States of Hopfield's Oxygen Emission Bands J. Chem. Phys. 38, 487 (1963); 10.1063/1.1733684 Effect of Molecular Oxygen on the Emission Spectra of Atomic OxygenAcetylene Flames J. Chem. Phys. 34, 1709 (1961); 10.1063/1.1701067

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tHE .tOURNAL OF CHEMiCAL PHYSiCS

Letters to the Editor

T HE Letters to the Editor section is subdivided into three parts entitled Communications, Comments and Errata, and Notes.

These three sections are all subject to the same limitations on length.

VOLUME 40, NUMBER 6

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15 MAR-ClI 1964

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Communications

Some New Emission Bands of Molecular Oxygen

S. J. ARNOLD, E. A. OGRYZLO, AND H. WITZKE

Chemistry Department, University of British Columbia, Vancouver, Canada

(Received 1 November 1963)

CALORIMETRIC, 1 spectroscopic,2 and mass spectro­metric3 studies of electrically discharged oxygen

have shown that the gas stream contains about 10% 02(1~g) and about 0.1 % 02(1~g+). In a spectroscopic search for other excited molecules present in the gas stream we have recorded two bands shown in Fig. 1 with peaks at 6340 and 7030 A. When oxygen atoms are removed by the addition of Hg to the discharge, the 6340 and 7030 A peaks remain unaltered while the 7600 and 8600 A peaks [(0, 0) and (0, 1) transitions in the 1~g+_3~g- system] are only slightly lowered.

The two new bands appear diffuse even with a spectral slit width of 0.6 A (Jarrell-Ash //6.3 grating spectro­graph). This fact together with their positions makes it obvious that they do not belong to the 1~g+-3~g­system.

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FIG. 1. Emission spectrum of electrically discharged oxygen with all atoms removed. Total O2 pressure=2 mm Hg. f/4.6 monochromator with an RCA-7102 photomultiplier. Solid line­slit 750/0<; broken line-slit 100 JIo.

reaction between Cb and H20 2 gives rise to a red emis­sion which was first reported by Seliger." The spectrum of the emission is shown in Fig. 2. There is no doubt that the emitter is the same as that in the discharge experiment. The extremely small 7600 A peak is con­sistent with the rapid quenching of 02(1~g+) by water in the discharge products.

Ozone cannot be the emitter since the addition of NO has no effect. Any excited molecules such as 02(3~u+) with a lifetime shorter than 0.1 sec would not be ob­served in our flow system. The 02(1~u- and 3~u+) states

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6340 7600

Two impurities could conceivably give rise to emis­sions in this region. Water absorption peaks have been observed at 6340 and 7000 A, and N02 emission bands are observed throughout this region.4 Hence specially dried, nitrogen-free oxygen was tried, and then both water and N02 were added before and after the dis­charge. The two new bands were essentially unaltered by these changes.

FIG. 2. Emission spectrum from the reaction of Cb and H20s An entirely different observation makes it even less in alkaline solution. Solid line-slit 250/0<; broken line-slit 100 p.

likely that this could be an "impurity" emission. The (and less amplification).

1769

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1770 LETTERS TO THE EDITOR

would not give rise to only two bands spaced 1550 cm-I

apart. In our opinion there remains only one other possible

source for these bands. The clue to the identification comes from the parallel behavior of the new bands and the 02(1l1g) concentration. Neither is affected by fewer than 106 collisions with any gas we have added. We therefore proposed the following reaction in which 0 4* and 0 4 may be stabilized by van der Waals forces:

(M) (M)

202(1l1g)~04*~04~202(3~g-)

+ hv

The 02(1l1g) dimer would then give rise to a band at 6343 A (when only ground vibrational levels are in­volved) and one at 7038 A [when an O2 (3~g-) molecule is left with one vibrational quantum]. Evidence for transitions such as this comes from studies of the absorp­tion spectrum of compressed oxygen.6 In an attempt to make the identification more certain we are undertaking a kinetic study of the relation between 02(1l1g) concen­tration and the new emission bands.

Note added in proof: Since this paper was submitted A. U. Khan and M. Kasha [J. Chem. Phys. 39, 2105 (1963)J have tentatively assigned the 6340 and 7030 A bands to solvent-shifted I~g+_3~g- transitions in oxygen. Since we have obtained these bands in the gas phase it is obvious the assignment must be in error.

* The research of this paper was supported by Defence Re­search Board of Canada, Grant Number 9530-31.

1 L. Elias, E. A. Ogryzlo, and H. 1. Schiff, Can. J. Chern. 37, 1680 (1959).

2 M. A. A. Clyne, B. A. Thrush, and R. P. Wayne, Nature 199, 1057 (1963).

3 S. N. Foner and R. L. Hudson, J. Chern. Phys. 25, 601 (1956). 4 A. Fontijn and H. 1. Schiff, Chemical Reactions in the Lower

and Upper Atmosphere (Interscience Publishers, Inc., New York, 1961), p. 239.

5 H. H. Seliger, Anal. Biochem. 1, 60 (1960). 6 V. 1. Dianov-Klokov, Opt. Spectry. 6, 290 (1959) [Opt. i

Spektroskopiya 6, 457 (1959)]. J. W. Ellis and H. O. Kneser, Z. Physik 86, 583 (1933).

Combination Lines in the Stimulated Raman Spectrum of Styrene*

D. P. BORTFELD AND M. GELLER

Aerospace Group, Httghes Aircraft Company Culver City, California

AND

GISELA ECKHARDT

Hughes Research Laboratories, Malibu, California

(Received 16 December 1963)

STIMULATED Raman scattering has been reported by several workers.I-4 In all cases only one, or, at

most, two of the known Raman shifts for the material

were active in stimulated emission. Moreover, although multiples of the stronger shift occur, no lines were observed which could be ascribed to combinations of the two shifts. Powe1l5 has reported such combination and multiple lines in the normal Raman spectrum of trans-hexatriene, but the effect was quite weak.

TABLE 1. Comparison of measured stimulated and normal Raman spectra of styrene.

Stimulated Raman spectrum

Normal Raman Anti- Calculated Assign-spectrum" Stokes" Stokes· shifts ments

210 235

488 533 617

772 835 906 938 998.7

1031 1081 1152 1178 1200 1243

1300 1315 1334

1413 1450 1496 1577 1600.7 1629.9

2982

3010 3060 3094

(2) (10)

(5) (6) (15)

(30) (2) (8) (2) (340) (15) (1) (15) (4) (65) (1)

(15) (30) (9)

(45) (4) (11) (20) (260) (410)

(5)

(15) (25) (8)

370

632

999

1263

1315

1367

1631 1998 2263 2630

2998

3056

369

630

999

1366

1626 1994

368±6 2Q-P

631±5 P-Q

998.7±1.6 Q

1262±9

Separate line

1367±8

1629.2±3.1 1997±3 2260±8 2628±5

2996±5

Separate line

2P-2Q

3Q-P

P 2Q 2P-Q P+Q

3Q

• All values in cne1 with an accuracy of 3 em-I unless otherwise stated. The numbers in parentheses are the relative strengths of the normal Raman shifts.

We report here the measurement of the stimulated Raman spectrum of styrene in which two strong Raman shifts (998.7 cm-1 and 1629.2 em-I) and two weak shifts (1315 cm-I and 3060 em-I) appear. Most evident in the spectrum are the lines which result from multiples, combinations and multiple combinations of the 998.7 cm-I (Q) line and the 1629.2 cm-I (P) line. In the first two columns of Table I we contrast the measured stimu­lated and normal Raman spectra. It is clear that with the exception of the four lines specified above, the ob­served lines do not appear in the normal Raman spec­trum. Using the Q and P shifts, we have calculated

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