## Rate constants for rotational excitation of CO by collisions with He atoms computed within the infinite order sudden (10s) approximation are compared with accurate quantum (coupled-states) and classical trajectory values Taking the 10s energy as the initial kinetic energy for upward, 0 -+J, tra
Accuracy of the IOS approximation for highly inelastic RET collisions
โ Scribed by F.A. Gianturco; M. Bernardi; M. Venanzi
- Publisher
- Elsevier Science
- Year
- 1990
- Tongue
- English
- Weight
- 626 KB
- Volume
- 165
- Category
- Article
- ISSN
- 0009-2614
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โฆ Synopsis
Inelastic collisions which give rise to rotational energy transfer (RET) at several different relative energies are examined for He and Ar projectiles interacting with Nz. Calculations are carried out within the infinite order sudden approximation (IOSA) for the dynamics and repeated more accurately by keeping the centrifugal sudden approximation (CSA) only in the quantum treatment of the multichannel scattering. It is shown that IOS invariably overestimates the CS cross sections, especially when high Aj transitions are involved. An average index to measure the overall efficiency of the RET processes is defined and compared within the two dynamical approximations. From such an index one can extract scaling corrections for the corresponding IOSA quantity and some measure of the global anisotropy for the chosen atom-diatomic potential surfaces.
๐ SIMILAR VOLUMES
Rate corMants for rotational cscitation of CO by coUisions with Ar atoms have been computed within the infmite order sudden (LOS) approximation and compared with values from csact cirtssical trajectories. For CO-Ar, as for CO-He, nccurale values for X(0-i) -at least for small and intcrmcdiatcj -may
The exponential Born approximation is used to compute S matrices and opacilies for rotational Eransitions in a model system corresponding to a heavy atom-heavy diatomic coilision. The rcsufts are in good agreement with the exact catculations in the limited coupling region. The use of the exponentia