Fluorescence of carbazole (Cz) was quenched by di-Me terephthalate (DMTP). In contrast to the system DMTP-ethylcarbazole (EtCz) fluorescence of exciplex was not observed The difference of exciplex formation ability between DMTP-EtCz and DMTP-Cz can be qual. explained by the fact that exciplex formation ability is not only dependent on the ionization potential of the donor and electron affinity of the acceptor but also dependent on the interaction between the side groups attached to the chromophores of the donor and acceptor mols.

Key words: CARBAZOLE P, P-BENZENEDICARBOXYLIC ACID P, M-BENZENEDICARBOXYLIC ACID P, CARBOXYLIC ACID ESTER, QUENCHING EFFECTS, O-BENZENEDICARBOXYLIC ACID P, FLUOROSPECTROPHOTOMETRY, FLUORSCENCE DECAY, EXCIMER, ELECTRON COLLISIONS