[en] The collision induced spectrum in equilibrium H₂(eH₂) and in equilibrium H₂--He mixtures have been determined at densities below 120 amagat in the region 500 to 900 cm/1 at 293, 195, and 77K. The collision induced spectrum of normal H₂ at 77K in the region 25 to 490 cm/1 has also been determined. The details of the experiment, experimental results, and comparison with previous results are presented. A report dealing with a new theory of the shape of pressure induced spectra with an application to the far infrared spectrum of eH₂ at 77K is appended

[en] In view of the importance of the equivalence between the prior-interaction and post-interaction forms for the validity of distorted-wave Born-approximation (DWBA) studies in reactive scattering, we present a comparison study between the two forms by illustrating a reactive atom--diatomic-molecule system. Our DWBA method presented earlier is found to satisfy the condition of the equivalence remarkably well

[en] This study presents the range of interesting phenomena which occur in reactions of 2exclamationD carbon and oxygen atoms with simple diatomic molecules. It is an extension of work done on O + H₂ as a function of collision energy. Each reaction is exothermic and at least one channel exhibits no barrier to reaction. The quasiclassical trajectory method was used and the results have been in semiquantitative agreement with experiment. The reactions can occur both by direct collisions and by the formation of tight collision complexes. Vibrational energy in the complexes appeared to be randomized quite rapidly. Rotational energy did not seem to be randomized significantly during the lifetimes of the complexes

[en] The results of two independent experiments and a theoretical calculation for the total collisional quenching cross section for H(2s) and D(2s) incident on He, Ar and H₂ targets are reported. One experiment (Wurzburg) was performed at low collision energies (from 0.1eV to 5eV), while the other experiment (Saclay) was conducted at higher collision energies (from 60eV to 3keV). Since the measured cross sections covered such a wide energy range, it was possible to use the experimental data to find the difference in the interaction potentials between the H(2s)+X and H(2p)+X systems, where X is the target gas

No abstract available

[en] Multichannel quantum-defect theory is extended to treat molecular dissociation processes simultaneously with ionization processes. Allowance is made for nuclear momentum coupling and for coupling with core excited channels. This theory combines the advantages of several less comprehensive approaches and is noniterative, nonperturbative, and applicable for arbitrary interaction strength. Several examples showing good agreement with experimental results relating to the H₂ molecule are given. copyright 1997 The American Physical Society

[en] Observed angular distributions for the reactive atom-diatomic molecule systems of rebound scattering appear to be 'classical' with non-oscillatory and backward-peaked shapes. How the partial waves interfere in their contribution to the state-to-state reactive scattering angular distributions has not been investigated. Here we report the coherent nature of relative (orbital) angular momenta (partial waves) in affecting the reactive state transition is simply. (Author)

[en] This paper discusses the theory of atom-diatom exchange collisions without breakup. Methods involving a direct solution of the Schroedinger equation by accurate and approximate techniques are described. The main focus is on reactions on single electronically adiabatic potential energy surfaces, with some consideration given to two electronic state calculations. (orig.)

No abstract available

[en] Total cross sections for quenching of metastable hydrogen and deuterium atoms in collisions with some selected molecules have been measured. The velocity range of the metastable projectiles is from 0.48 to 3.6x10⁶cm/sec. The cross sections have been compared with the predictions of two theoretical treatments by Gersten and Semini which both assume collisional quenching to be due to the interaction of the metastable atom with the molecule's lowest order electric multipole moment