Abstract

Vibrational excitation in particular bonds strongly influences chemical reaction rates in all phases. Energy transfer at surfaces is important in physical processes such as sticking, desorption, diffusion and chemistry of oxidation, catalysis, and electronic materials processing. Until recent ultrafast laser experiments, information on rates and mechanisms of vibrational energy dissipation in large molecules or in condensed phases came from theory or was inferred from linewidths of optical spectra. We have used tunable picosecond and femtosecond IR laser pulses in pump-probe experiments to obtain time-resolved information about energy flow for high-frequency vibrations (e.g., NH, OH, NO, CO stretching modes) of molecules in the gas phase or dissolved in solvents and for ordered monolayer and submonolayer coverage of CO on the surface of single crystal Pt(111).

© 1991 Optical Society of America