IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Surface Science Friday Sessions
       Session SS2-FrM

Paper SS2-FrM5
Ultrafast Energy Flow Studied by Femtosecond Vibrational Spectroscopy

Friday, November 2, 2001, 9:40 am, Room 121

Session: Gas-Solid Dynamics: Theory and Experiment
Presenter: M. Bonn, Leiden University, The Netherlands
Authors: S. Roke, Leiden University, The Netherlands
A.W. Kleyn, Leiden University, The Netherlands
M. Bonn, Leiden University, The Netherlands
Correspondent: Click to Email
We present a simple model describing femtosecond surface vibrational spectroscopy as a tool to study ultrafast surface chemical dynamics. We compare our calculations to recent experiments in which the interaction between CO and the Ru(0001) surface is studied using the femtosecond surface vibrational spectroscopy: sum frequency generation (fs-SFG). After short-pulsed excitation of the metal leading to desorption of CO, a transient red-shift and broadening in the infrared spectrum of the C-O stretch vibration on a picosecond time-scale are observed. The data are successfully modeled by considering the response of adsorbed CO to heating of the system by a femtosecond laser pulse. The calculations match the experimental data very well and demonstrate that fs-SFG is a very powerful tool to study the dynamics of molecules at surfaces. Detailed analysis shows that this method will enable us to detect transition states and reaction intermediates in chemical reactions at surfaces and determine the transition state lifetime. Results of first experiments on energy flow in a reacting system will be shown at the meeting.