TWISTED INTRAMOLECULAR CHARGE-TRANSFER STATES IN SUPERCOOLED MOLECULES - STRUCTURAL EFFECTS AND CLUSTERING WITH POLAR-MOLECULES

This paper presents a study of laser-induced fluorescence and excitation spectra of jet-cooled 4-(dimethylamino)benzonitriles and 4-(dialkylamino)pyrimidines and their complexes with small polar molecules (methanol and acetonitrile). Various ground-state forms (monomers, dimers, and larger clusters) have been observed. The bare molecules (except III) do not exhibit any distinct long-wave fluorescence that can be assigned to a twisted intramolecular charge-transfer (TICT) state. Microsolvation of pretwisted compounds by small polar molecules gives rise to a long-wave fluorescence, which is interpreted as emission from a TICT state.