The geometries of eight unsymmetrical squaraine dyes have been optimized by ab initio method at the 6-31G(d,p) basis set. The quantitative relationships between their intramolecular charge- transfer degrees and their dark decay values, their photosensitivity, and the largest wavelengths of their absorption spectra have been studied. The results indicate that their intramolecular charge- transfer characteristics is an important factor which affects their photoconductivity and the largest wavelengths of their absorption spectra.

Key words: ASYMMETRY, SQUARIC ACID, DYES, ELECTRONIC STRUCTURE, ORGANIC PHOTOCONDUCTOR, INTERNAL MOLECULAR REACTION, PHOTOCONDUCTIVE MATERIAL, CHARGE TRANSFER, AB INITIO CALCULATION