Spin–orbit ab initio study of alkyl halide dissociation via electronic curve crossing
|Title||Spin–orbit ab initio study of alkyl halide dissociation via electronic curve crossing|
|Publication Type||Journal Article|
|Year of Publication||2004|
|Authors||Devarajan A, Wierzbowska M, Lindh R, Malmqvist PA|
|Journal Title||Journal of Chemical Physics|
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-σ∗ states are studied including spin–orbit and relativistic effects. Basis set including effect of core correlation is used. Ab initio vertical excitation spectra of CH3I and CF3I are in agreement with the experimental observation. The curve crossing region is around 2.371 Å for CH3I and CF3I. The potential curves of the repulsive excited states have larger slope for CF3I, suggesting a higher velocity and decreased intersystem crossing probability on fluorination. We also report the potential curves and the region of curve crossing for CH3Br and CH3Cl.