Abstract

Solids of N.N-Dimethylaminobenzylidene 1,3-indandione (DMABI) are typical examples of polar organic crystals, which are built-up by dipolar molecules. The large static dipole moment of the DMABI molecule in the ground state and particularly its change by excitation (up to 12 D) induces a large polarisation effect of the surrounding, responsible for remarkable lattice reorganisation effects [1]. Our previous studies of self-trapped excitonic states in DMABI solids showed that polar DMABI crystals are organic systems characterized by a strong exciton-phonon coupling (the exciton-phonon coupling constant was estimated, g=1.87) [2,3]. It was also shown that excitons in DMABI crystals correspond to intermolecular charge transfer (CT) states resulting from a well expressed stacked crystal structure [3].

© 1998 IEEE