The photochemistry of 1,3-butadiene rationalized by means of theoretical resonance structures and their weights
A complete active-space self-consistent-field wave function for the pi-electron part of s-trans-1,3-butadiene has been expanded into a set of localized bonding schemes and their weights. These bonding schemes are close to the resonance structures used in organic chemistry. The expansion technique has been applied to both the electronic ground state and the electronically first-excited singlet and triplet pi,pi* states. The manifolds of large-weight bonding schemes represent approximate resonance hybrids for the ground and the singlet and triplet pi,pi* states of s-trans-1,3-butadiene. These resonance hybrids, obtained by theory alone, permit a qualitative rationalization of a significant part of the known singlet and triplet photochemistry.
Bachler
V
Max-Planck-Institut fur Strahlenchemie, Mulheim an der Ruhr, Germany. bachler@mpi-muelheim.mpg.de
Schaffner
K