IN-SITU SFG SPECTROSCOPY OF FILM GROWTH - I - GENERAL FORMULATION ANDTHE ANALYSIS OF THE SIGNAL OBSERVED DURING THE DEPOSITION OF FORMIC-ACID ON PT(110)-(1X2) SURFACE

The application of infrared-visible sum-frequency generation (SFG) spe ctroscopy to the in situ monitoring of film growth was examined by the observation of the growth of the physisorbed layer of formic acid on a reconstructed Pt(110)-(1x2) surface. The signal by the CH stretching band displayed a characteristic interference pattern as deposition pr oceeded at 158 K to prove that the signal originated from inside the d eposited film and the CH bond and molecular plane of formic acid was a ngled to the surface. The expressions for the electric fields of the S F beams generated inside the film, at the top layer, and at the bottom layer were derived by incorporating the interference effects of the e xciting and generated light beams. The formula was used to simulate th e observation and to estimate the growth rate. (C) 1998 American insti tute of Physics.