Validity of the adiabatic approximation for vibrational energy transfer in collisions between diatomic molecules

✍ Scribed by John P. Dwyer; Aron Kuppermann

• Publisher: Elsevier Science
• Year: 1976
• Tongue: English
• Weight: 297 KB
• Volume: 44
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(76)80714-2

✦ Synopsis

Accurate quantum mechanical transition probabilities for vIbrationa to vibrational and vibrational to translational cncr-

gy txm\fcr in collmcar colliaons of two hydrogen molecules were calculated for a model pootentki by numerica integration of the Sduodmgcr equation. The accuracy of these calculations was checked by conserration of flux and convcrgcncc tests and by verifymg that they satMcd a rigorous theorem proven by Clarke and Thicle. These accurate resuItr were then u\cd to dctcrminc the range of vahdlty of the adiabatic approximtion of Thick: and Katz as applied to this modc1 system by Clarke and Thicic. Tius approximation yielded probabrhties which agreed with the accurate ones to 10% or better for Lotal energies E up to 6.1 (in umts of diatom vibra:ionaI quanta). However, at E = 7.9 these appro.simatc resutts conId be off by a factor of 1 5 or higher. t Research supported in part by the Air Fora: Office of Sclcntific Rcscarch, Grant AFOSR 73-2539. * In partial fulfilsnent of the requirements for the Ph.D. degee in Chemistry at the California Institute of Technology. * Contabution No. 5395.