Recently the conception on the cis-trans photoisomerization of stilbene has emerged that this process is governed by a higher excited 1Ag state which exhibits a minimum at the perpendicular conformation crossing the lowest excited 1Bu state upon bond rotation. An evaluation of the potential surfaces governing the photoisomerization process by a PPP SCF CI method revealed that there exists indeed such a photochemically active 1Ag state which in the planar molecule lies about 1 eV above the lowest absorption band and involves the excitations of two electrons from the SCF ground state. Extensions of the calculations to diphenylpolyenes demonstrate that this 1Ag state is related to the forbidden low-lying doubly excited 1Ag state observed earlier in these molecules.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry