Spin-orbit ab initio study of alkyl halide dissociation via electronic curve crossing

D Ajitha; M Wierzbowska; R Lindh; P A Malmqvist

doi:10.1063/1.1784411

Spin-orbit ab initio study of alkyl halide dissociation via electronic curve crossing

J Chem Phys. 2004 Sep 22;121(12):5761-6. doi: 10.1063/1.1784411.

Authors

D Ajitha¹, M Wierzbowska, R Lindh, P A Malmqvist

Affiliation

¹ Department of Theoretical Chemistry, Chemical Center, Lund University, P.O. Box 124, S-221 00 Lund, Sweden. ajitha.devarajan@teokem.lu.se

PMID: 15367000
DOI: 10.1063/1.1784411

Abstract

An ab initio study of the role of electronic curve crossing in the photodissociation dynamics of the alkyl halides is presented. Recent experimental studies show that curve crossing plays a deterministic role in deciding the channel of dissociation. Coupled repulsive potential energy curves of the low-lying n-sigma(*) states are studied including spin-orbit and relativistic effects. Basis set including effect of core correlation is used. Ab initio vertical excitation spectra of CH(3)I and CF(3)I are in agreement with the experimental observation. The curve crossing region is around 2.371 A for CH(3)I and CF(3)I. The potential curves of the repulsive excited states have larger slope for CF(3)I, suggesting a higher velocity and decreased intersystem crossing probability on fluorination. We also report the potential curves and the region of curve crossing for CH(3)Br and CH(3)Cl.