CORRELATION AND RELAXATION EFFECTS IN THE ELECTRONIC COUPLING BETWEEN ACETYLENIC-PI AND PI-ASTERISK-ELECTRONS THROUGH SATURATED AND AROMATIC SPACERS

The electronic factor A for electron and hole transfer between two acetylene molecules connected by the saturated 1,3-bicyclo[1,1,1]pentane and 1,4-bicyclo [2,2,2]octane bridges and the unsaturated phenyl bridge is calculated using different correlation-corrected ab initio methods, particularly the multiconfigurational second-order perturbation theory (CASPT2) of Roos et al. Correlation and relaxation effects improve the agreement between calculated and experimental results.