Mj. Weida et Cs. Parmenter, ALIGNING SYMMETRICAL AND ASYMMETRIC-TOP MOLECULES VIA SINGLE-PHOTON EXCITATION, The Journal of chemical physics, 107(18), 1997, pp. 7138-7147
The theory developed by Zare [Ber. Bunsenges. Phys. Chem. 86, 422 (198
2)] for using electric-dipole-allowed photoexcitation with linearly po
larized light to align linear and symmetric top molecules via parallel
transitions is extended to include perpendicular transitions, as well
as the alignment of asymmetric tops via a-, b-, or c-type transitions
. Analytical expressions for the spatial distribution of a symmetric t
op figure axis following a parallel or perpendicular transition are pr
esented. A prescription is developed for determining the spatial distr
ibution of each principal axis of an asymmetric or symmetric top follo
wing parallel or perpendicular type transitions. The degree of alignme
nt obtainable via photoexcitation for symmetric and asymmetric tops is
discussed, with the somewhat surprising result that all three princip
al axes of an asymmetric top can be highly aligned via photoexcitation
. A simple computer program for calculating the degree of alignment of
each principal axis of a symmetric or asymmetric top following an a-,
b-, or c-type transition is described and made available. (C) 1997 Am
erican Institute of Physics.