W. B. Olson

Studies of Hydrogen Peroxide: The Infrared Spectrum and the Internal Rotation Problem

Several hydrogen peroxide infrared absorption bands have been obtained under 0.2 cm—1 resolution. They demonstrate both doubling due to internal rotation and effects due to the inertial asymmetry. The ground‐state rotational constants are found to be: A″=10.068 cm—1, B″=0.8740, C″=0.8384. These parameters indicate a wide dihedral angle for H2O2, as proposed in the following structure: OO bond=1.475 A, OH bond=0.950 A, dihedral angle=119.8°, and OOH angle=94.8°.The constants are applied to the microwave data for H2O2 and the deuterated species. The ground‐state splitting is found to be 11.44 cm—1, and this, used with the recently reported torsion at 317 cm—1, yields the barriers hindering internal rotation. They are Vcis=1300 cm—1 and Vtrans=300 cm—1. A simple correlation of the infrared doublings is attempted.

Infrared collision-induced absorption by O 2 near 6.4 µm for atmospheric applications: measurements and empiricalmodeling

Accurate measurements of collision-induced absorption by O(2) and O(2)-N(2) mixtures in the fundamental band near 6.4 microm have been made. A Fourier-transform spectrometer was used with a resolution of 0.5 cm(-1). Absorption has been investigated in the 0-20-atm and 193-293 K pressure and temperature ranges, respectively. The current measurements confirm that the broad O(2) continuum carries small features whose attribution is not yet clear. Available experimental data in the 190-360 K temperature range have been used to build a simple, low cost computer, empirical model that is well adapted for computation of atmospheric O(2) absorption. Tests show that it is accurate, contrary to predictions of widely used atmospheric transmission codes.

Rotational constants of the lowest torsional component (0G) of the ground state and lowest torsional component (1G) of the first excited torsional state of hydrogen peroxide

Abstract New high-resolution spectra of hydrogen peroxide has been taken in the OH stretching region and in the overtone-combination region of the OOH bends. Ordinary combination differences in the (0G) and (1G) torsional states and directly obtained energy level differences between these torsional states have been supplemented with combination differences obtained from previously published microwave data and fitted to obtain the rotational constants of the two torsional states and the parameter characterizing the perturbation between them. A simplified notation scheme for the vibrational-torsional-rotational levels, the transitions used to obtain direct energy level differences between levels of the (0G) and (1G) torsional states, and the specific Hamiltonian used are described in the text. A table of rotational and interaction constants is given, and also tables of the actual (perturbed) rotational levels in the (0G) and (1G) torsional states.

Tables of N2O Absorption Lines for the Calibration of Tunable Infrared Lasers from 522 cm(-1) to 657 cm(-1) and from 1115 cm(-1) to 1340 cm(-1),

Data from the literature has been critically selected and refitted by least squares to provide accurate vibrational band centers and rotational constants for three bands of N2O. The line positions of the bands have been calculated from the constants of the fits to provide accurate absorption line positions to serve as wavelength standards in the regions of 522 cm−1 to 657 cm−1 and from 1115 cm−1 to 1340 cm−1 in the infrared.

The infrared spectrum of thioformaldehyde

Abstract The infrared spectrum of thioformaldehyde (H 2 CS) has been observed in the CH stretching region. The spectrum was obtained under conditions of high resolution and rotational analyses have been carried out on the three observed bands. The main results (in cm −1 ) for the excited states are: Band ν 0 A B C ν 5 3024.61 9.675 0.5893 0.5554 ν 1 2971.03 9.648 0.5907 0.5542 2ν 6 (?) 2877.11 9.821 0.5936 0.5533 Several local perturbations have been observed in the two fundamentals ν 5 and ν 1 . These are presumably caused by overtones and combinations of the lower lying fundamentals but it has not been possible to make specific assignments of the perturbing levels.

Infrared determination of C0 for phosphine via perturbation‐allowed Δ |k − l|= ± 3 transitions in the 3ν2 band

The 3ν2(A1) and 4ν2−ν2(A1) infrared bands of PH3 have been measured with high resolution. In the ν2=3 state an interaction between the K and K±3 levels gives rise to perturbation allowed ΔK = 3 transitions through a weak high order interaction. Since only one component of the K = 3 levels is of the proper symmetry to interact with the K = 0 levels there is a splitting of the K = 3 levels. Also detectable is the splitting of the K = 3 levels of the ground vibrational state. The measurements have been combined with microwave measurements to give accurate values for the ground state rotational constants B0, C0, D0J, D0JK, D0K, H0J, H0JJK, and H0JKK. The absence of observable inversion effects sets an upper limit of about 0.02 cm−1 for the inversion splitting of the 4ν2 level.

Infrared measurements on arsine: ν1 and ν3 bands, perturbation-allowed transitions, equilibrium structure

Abstract High resolution infrared measurements are reported on arsine (AsH 3 ) from 2260 to 1960 cm −1 . Numerous perturbation-allowed transitions have been found and are used to determine the C 0 rotational constant. Ten ground state rotational constants are determined including one that describes the splitting of the k = 3 levels. A complete equilibrium structure is determined. A total of 26 upper state constants are determined by means of a computer program which simultaneously fits both ν 1 and ν 3 bands and includes many off-diagonal matrix elements. This analysis will fit transitions through J = K = 12 to within experimental error, but it is concluded that to fit higher rotational transitions the perturbing effects of 2 ν 4 must be taken into account explicitly.

Pollution Monitor for Nitric Oxide: A Laser Device Based on the Zeeman Modulation of Absorption

The Concentration of nitric oxide can be monitored by a new device in which the Zeeman effect is used to shift an absorption line of nitric oxide into coincidence with a laser line of carbon monoxide. The absorption is modulated by a small, oscillating magnetic field. This device is specific for nitric oxide and is not subject to interference from other gases.

The infrared spectra of 12C32S, 12C34S, 13C32S, and 12C33S

Abstract Using a tunable diode laser spectrometer, the infrared absorption spectra of four isotopic species of carbon monosulfide have been observed in the positive column of a dc discharge of CS2 and Ar. The wavenumbers of 115 vibration-rotation transitions between 1180.5 and 1266.1 cm−1 have been measured. These lines were assigned to the 1-0, 2-1, 3-2, and 4-3 bands of 12C32S, the 1-0 and 2-1 bands of 12C34S and 13C32S, and the 1-0 band of 12C33S. These new data have been combined with the previous infrared and microwave results to determine Dunham coefficients (Yij), the Dunham potential expansion constants (a0,a1,a2,a3, and a4), and the classical turning points by the RKR method.

The high-resolution infrared spectra of the ν2 and ν3 bands of HOCl

Abstract The infrared spectra of the a -type transitions of the ν 2 and ν 3 bands of HO 35 Cl and HO 37 Cl have been obtained under high resolution. Line assignments of both bands have been made, and the spectroscopic constants have been obtained for both bands using a Watson Hamiltonian. Lines of the K a = 5 subband of the ν 2 band of the HO 35 Cl molecule were found to be slightly shifted by an interaction with the K a = 4 level of the 2 ν 3 vibrational state. The b -type transitions permitted for both bands were too weak to observe. Relative intensities of selected lines of both bands have been measured, and empirical Herman-Wallis factors have been determined.