Fully converged sudden rotation total integral cross sections for 4He + H2 (ν = 0, j = 0) → 4He + H2 (ν′ = 1, j′)
1977; Elsevier BV; Volume: 48; Issue: 1 Linguagem: Inglês
10.1016/0009-2614(77)80244-3
ISSN1873-4448
AutoresSteven C. Leasure, Joel M. Bowman,
Tópico(s)Molecular Spectroscopy and Structure
ResumoAbstract Total integral cross sections for 4 He + H 2 (ν = 0, j = 0) → 4 He + H 2 (ν′ = 1, j ′ = 0, 2) have been calculated in the total energy range 1.2 to 5.5 eV, according to a quantal sudden approximation for the H 2 rotational degrees of freedom and a close coupling expansion of the vibrational degree of freedom. Convergence of the above cross sections is investigated by employing four vibration basis sets in the close coupling calculations, i.e., ν = 0,1, ν = 0,1, 2, ν = 0, 1, 2, 3 and ν = 0, 1, 2, 3, 4. Between 4.2 and 5.5 eV calculations were done with three vibration basis sets; ν = 0.–4, ν = 0–5, and ν = 0–6. It is found that at least four vibrational basis functions are needed to converge (to within 5–10%) these cross sections in the above energy range. Comparison of breathing sphere calculations and summed sudden rotation results shows good agreement for the (weakly anisotropic) Mies-Krauss potential. However, as expected the former results underestimate the vibrational 0 → 1 total integral cross sections.
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