Optical control of yields of CO photodesorbed from Cu(001) by chirped light pulses: density matrix theory and calculations

Yields of CO photodesorbed from Cu metal surfaces by absorption of femtosec ond chirped pulses of visible light are obtained within a density matrix ap proach, including the non-linear optical response of the substrate for puls es of large fluence. Our model is based on potential energy surfaces, coupl ings and transition dipoles parametrized from electronic structure calculat ions for CO/Cu. Results show that the yields of desorbed CO can be controll ed by both positive and negative chirping, to obtain either a suppression o r an enhancement of the yield. The effect can be as large as a doubling of the yields. (C) 1998 Elsevier Science B.V. All rights reserved.