On the π–π* spectra of 1-phenylbutadiene and 1-phenylhexatriene. A theoretical study including electron correlation

Abstract

The π→π* spectra of 1-phenylbutadiene, 1-phenylhexatriene and, for comparison, styrene are calculated using the Pariser–Parr–Pople method with doubly and triply excited configurations included. The results are consistent with the available experimental data. In each case, the state corresponding to the 2 ¹A_g state of polyenes is calculated to be the third lowest excited state and to lie just above the state responsible for the “conjugation band”.