Absorption spectra of H sub 2 -H sub 2 pairs in the fundamental band

Journal Article · Fri Dec 15 00:00:00 EST 1989 · Physical Review (Section) A: General Physics; (USA)

DOI:https://doi.org/10.1103/PhysRevA.40.6931· OSTI ID:7274083

Meyer, W ^[1]; Borysow, A ^[2]; Frommhold, L ^[3]

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1. Fachbereich Chemie der Universitaet, D-6750 Kaiserslautern, Federal Republic of Germany (Germany, F.R.)
2. Joint Institute for Laboratory Astrophysics University of Colorado, Boulder, Colorado 80309-0440 (USA)
3. Physics Department, University of Texas at Austin, Austin, Texas 78712-1081 (USA)

For the computation of the induced-dipole moment, the collisional complex consisting of two H{sub 2} molecules is treated like one molecule in the self-consistent-field and size-consistent, coupled electron pair approximations that separates correctly at distant range. The basis set accounts for 95% of the correlation energies. The radial transition matrix elements of the induced-dipole components are obtained for the two cases {ital v}{sub 1}=v{sub 2}=0 and {ital v}{sub 1}=0,{ital v}{sub 2}=1, where the {ital v}{sub {ital i}} are the vibrational quantum numbers of the interacting H{sub 2} molecules ({ital i}=1 or 2). The dependence of these elements on the most important rotational states ({ital j}{sub 1}, {ital j}{sub 1}{prime},{ital j}{sub 2},{ital j}{sub 2} {prime}=0,...,3) involved is obtained and seen to be significant in the fundamental band. The results are recast in a simple, but accurate analytical form that is used in a quantum formalism for computations of the spectral moments (sum rules) and line shapes of the collision-induced absorption spectra of molecular hydrogen pairs in the infrared 2.4-{mu}m band. The calculations are based on a proven isotropic potential model that we have extended to account for effects of vibrational excitations. Numerical consistency of the line-shape calculations with the sum rules is observed at the 1% level. The comparison of the computational results with the available measurements at temperatures from 20 to 300 K shows agreement within the estimated uncertainties of the best measurements ({approx}10%). This fact suggests that theory is capable of predicting these spectra reliably at temperatures for which no measurements exist, with an accuracy that compares favorably with that of good laboratory measurements.

• OSTI ID: 7274083
• Journal Information: Physical Review (Section) A: General Physics; (USA), Vol. 40:12; ISSN 0556-2791
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
HYDROGEN
ABSORPTION SPECTRA
BOUND STATE
INFRARED RADIATION
MOLECULAR MODELS
ROTATIONAL STATES
TWO-BODY PROBLEM
ELECTROMAGNETIC RADIATION
ELEMENTS
ENERGY LEVELS
EXCITED STATES
MANY-BODY PROBLEM
MATHEMATICAL MODELS
NONMETALS
RADIATIONS
SPECTRA
640302* - Atomic
Molecular & Chemical Physics- Atomic & Molecular Properties & Theory