Excited state molecular dynamics simulations of nonlinear push-pull chromophores

Julolidinemalononitrile, p-nitroaniline, and julolidinyl-n-N,N'-diethylthiobarbituric acid are studied with ground and excited state molecular dynamics simulations in conjunction with the collective electronic oscillator formalism and Onsager's cavity model. Ground and excited state geometries are calculated in the gas phase and four solvents. The results are interpreted in the context of a two-state valence bond model for charge-transfer transitions of conjugated organic molecules, and are compared to recent resonant Raman experimental results. The calculated geometries are qualitatively consistent with both the two-state model and experiment. In addition, calculated transition density matrices are presented to visualize the changes in charge distribution accompanying photoexcitation. (C) 2002 Elsevier Science B.V. All rights reserved.