| Abstract
| - In this work, both static and dynamic aspects of the Z → E photoisomerization of the (Z)-pentadieniminiumcation, a minimal model of retinal (the chromophore of rhodopsin proteins), are investigated on the basis ofab initio CASSCF potential energy surfaces taking into account the full set of vibrational degrees of freedomof the molecule. In particular, the structure of the lowest lying one-dimensional cross-section of the intersectionspace formed by the S1 and S0 energy surfaces has been mapped along the Z → E isomerization of the centraldouble bond from 0° to 180°. The evolution of a semiclassical wave packet toward the S1/S0 intersectionseam on the basis of 70 independently calculated zero-point energy sampled trajectories has been examined.The results indicate that the photodynamics of the Z → E isomerization is controlled by a small segment ofthe intersection space which intercepts the excited-state reaction path. In addition to the effects of surfacetopography, the influence of the kinetic energy on the rate of the Z → E isomerization is also investigated.
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