Collect. Czech. Chem. Commun. 1990, 55, 2874-2879

MNDO CI study of the photoisomerization of pentadieniminium

Peter Ertl

Chemistry Institute, Comenius University, 842 15 Bratislava


Photoisomerization mechanism in model retinal-like protonated Schiff base pentadieniminium was investigated by using MNDO method with configuration interaction. Isomerizations around various double bonds were studied and twisted biradical geometries in S0 and S1 states were optimized. Photoisomerization proceeds exclusively around the central double bond where the twisted S1 state is strongly stabilized and the S0-S1 gap is minimal.