SYMMETRY AND ORIENTATIONAL STRUCTURE IN HEMICYANINE MONOLAYER BY SURFACE 2ND HARMONIC-GENERATION AND ABSORPTION-SPECTROSCOPY

We have investigated the influence of the deposition process on hemicyanine monolayer structure by surface second harmonic generation (SHG) and absorption spectroscopy. The H-aggregates tend to dissociate by deposition. The orientation of the H-aggregates in the pure hemicyanine monolayer changes through the deposition process; the molecular long axes of the H-aggregate are parallel to the surface normal in the LB film made by vertical deposition, while their average direction makes a certain angle with respect to the surface normal in the LB film made by horizontal deposition.