Second harmonic generation studies of metal and nonmetal porphyrins at silica surfaces

ECHEVARRIA, LORENZO; PISCITELLI, VINCENT; CASTILLO, JIMMY; SCOTT, CARLOS; CAETANO, MANUEL

DENVER

Congreso; SPIE's International Symposium on Optical Science, Engineering, and Instrumentation; 1999

spie

Resonant molecular optical second harmonic generation (SHG) was obtained from(2, 3, 7, 8, 12, 13, 17, 18-Octaethyl- porphinato)M, with M equals none, vanadyl and Ni(II), adsorbed onto fused silica substrates. The polarization dependence of the SHG signals at 1064 nm allowed the determination of average molecular orientations. For the vanadium porphyrin the average angle between the long axis molecules and the surface normal was 38 degrees, while, for the Nickel porphyrin, and the non-metal porphyrin the angle was close to 0 degrees. These results can be understood in terms of the different symmetries of the molecules.