T. H. Edwards

Ground‐State Molecular Constants of Hydrogen Telluride

The ground states of the five isotopic species H2130Te, H2128Te, H2126Te, H2125Te, and H2124Te have been analyzed by simultaneous least‐squares fits of ground‐state combination differences formed from the four bands ν1 + ν2, ν2 + ν3, 2ν1, and ν1 + ν3. Values have been obtained for the ground‐state constants A, B, C, the four centrifugal distortion taus, and the empirical term HK added to the second‐order Hamiltonian, for each of these species.

Vibrational Analysis and Isotope Effects in Hydrogen Selenide

Values of the band origins for the near‐infrared rotation—vibration bands v1+v2, v2+v3, 2v1+v3, v1+2v3, 3v1, and 3v1+v3 of H280Se were determined directly from their respective PPJ (J) and RRJ (J) lines. A vibrational analysis of the band origins of these six bands, of four previously analyzed combination bands, and of the three fundamentals led to values for the zero‐order frequencies, anharmonic constants, and the interaction matrix element for a second‐order resonance between levels of the type (v1, v2, v3) and (v1−2, v2, v3+2). Values for the isotopic band center separations Δv0≡v0 (H280Se) —v0 (H2iSe) and for ΔC0≡80C0−iC 0, where i=82, 78, 77, and 76, were obtained from the observed isotopic separations of the PPJ (J) and RRJ (J) lines for several bands. These empirical values of Δv0 are compared with a set of theoretical values calculated using Krimms approximate isotopic frequency rule and the vibrational constants for H280Se. Values of iA0, iB0, and iC0 were calculated by combining our values of ...

Analysis of 2ν2, ν1, and ν3 of H2Se

Abstract We have run high-resolution infrared absorption spectra of 2 ν 2 , ν 1 , and ν 3 of H 2 S in the region 4.6 to 3.5 μm. We have identified and fitted approximately 350 transitions in 2 ν 2 , 260 transitions in ν 1 , and 130 transitions in ν 3 . The 2 ν 2 transitions include 45 lines from H 2 34 S. Using Typkes Hamiltonian, we analyzed 2 ν 2 as a single noninteracting band and analyzed the Coriolis interacting bands ν 1 and ν 3 simultaneously. Ground-state constants were obtained from a simultaneous fit of the microwave transitions, our ground-state combination differences, and averaged ground-state combination differences from ν 1 + ν 2 , ν 2 + ν 3 , ν 1 + ν 2 + ν 3 , and 2 ν 1 + ν 2 . Our upper-state constants were obtained from least-squares fits of our spectral lines for 2 ν 2 and for ν 1 and ν 3 , keeping the ground-state constants fixed. Our attempts to analyze all three bands simultaneously failed to yield a value for the Fermi interaction constant.

Analysis of ν2 of H233S and H234S

Abstract We have extended our analysis of the (010) vibrational state of H 2 S, this time using Watsons A -reduced Hamiltonian (through P 8 terms) in the I ′ rotational representation. We have determined separate sets of (010) upper state constants for each isotopomer (H 2 32 S, H 2 33 S, and H 2 34 S) by fitting the ν 2 spectral lines, keeping the ground state constants fixed to the values determined by Flaud, Camy-Peyret, and Johns. Determinable coefficients for H 2 32 S and a slightly revised set of ν 2 line assignments for H 2 33 S and H 2 34 S are also reported.

Infrared Spectra of the Methyl Halides. II. Methyl Bromide near 4450 cm—1

Three overlapping perpendicular bands of CH3Br are assigned in this work to ν2+ν4 at 4352.58, ν4+ν5 at 4446.03, and ν1+ν3+ν6 at 4482.39 cm—1. Of these, ν4+ν5 is relatively weak, and the analysis was based on directly measured frequencies of the sharp Q branches. The analyses of the other two bands were based on many individual lines in the P and R branches of the subbands.

Simultaneous analysis of the 2ν1 and ν1 + ν3 bands and the equilibrium structure of hydrogen telluride☆☆☆

Abstract The Coriolis coupled vibration-rotation bands 2 ν 1 and ν 1 + ν 3 of H 2 Te, which overlap near 4063 cm −1 , have been analyzed by fitting the lines from all of the Te isotopes simultaneously. Using the resulting rotational constants for the ν 1 + ν 3 band and those previously obtained for the ν 1 + ν 2 , ν 2 + ν 3 , and ν 2 along with the ground state constants, a set of αs was determined. From the αs the equilibrium rotational constants A e = 6.2515 cm −1 and B e = 6.1036 cm −1 were calculated and then the equilibrium HTeH bond angle of 90°15′ and an equilibrium bond length of 1.658 A were calculated.

Simultaneous analysis of the ν1 + ν2 and ν2 + ν3 bands of hydrogen telluride☆☆☆

Abstract The vibration-rotation absorption bands ν1 + ν2 and ν2 + ν3 of H2Te, which overlap one another near 2900 cm−1, have been analyzed using recently developed formulas. Because the upper states of these two bands are coupled through the interaction terms Gc(q1p3 − q3p1)Pz and Gabq1q3(PxPy + PyPx) in the Hamiltonian, we have analyzed them simultaneously by numerically diagonalizing the perturbed planar Hamiltonian matrix with the interaction terms included. The observed absorption lines from the six most abundant tellurium isotopes have been fit simultaneously by including mass dependencies for the terms A, C, and ν0 for upper and ground states. Values have been determined for the upper state constants ν0, A, B, C ∗ the four centrifugal distortion taus, and the sixth power term HK for each of the two bands, the interaction terms Gc and Gab between the two bands, and the ground state constants, as well as the mass dependency terms.

An X-Y Coriolis perturbation in ν4 of CD3Br

Abstract The region 2242–2273 cm −1 of the ν 4 band in CD 3 Br was remeasured at a resolution limit of 0.025 cm −1 . Line assignments were extended up to J = 50 in some subbands. Transitions in the K Δ K = −8 subband were assigned, and the perturbation apparent in this region was attributed to the x - y Coriolis interaction with ν 3 + ν 5 ±1 + ν 6 ±1 . The x - y Coriolis coupling parameter W xu and the ν 3 + ν 5 ±1 + ν 6 ±1 band center (in cm −1 ) are 0.01960 and 2339.17 for CD 3 79 Br, while the corresponding values for CD 3 81 Br are 0.01956 and 2337.95.

Analysis of 2ν1 of HDSe

Abstract We have run a high resolution infrared absorption spectrum of HDSe in the 2.2 μm region. We have assigned it to 2 ν 1 , the SeH stretch overtone of HDSe, and have identified a total of approximately 300 transitions among the isotopic species containing Se isotopes 82, 80, 78, 77, and 76. We analyzed all isotopes simultaneously using Typkes reduced Hamiltonian. Ground state constants were obtained from a simultaneous least squares fit of our ground state combination differences together with Veselagos microwave data. Upper state constants were obtained from a least squares fit of our spectral lines, keeping the ground state constants fixed.

Electric‐Field‐Induced Spectra of Hydrogen Cyanide

Electric‐field‐induced spectra (efs) of several absorption bands of HCN were experimentally produced and shown to exhibit the following phenomena: each of the three limiting case efs line shapes predicted by N. J. Bridge, D. A. Haner, and D. A. Dows [J. Chem. Phys. 48, 4196 (1968)], viz., normal, first derivative, and second derivative; two distinct types of induced transitions which are forbidden in the zero‐field case; and l‐type doubling enhancement of electric field effects. Although experimental conditions were such as to render the validity of a weak field approximation doubtful, line shapes as well as transition frequencies were found to agree with predictions based upon that assumption.