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Time evolution of CO vibrational populations during photodesorption by light pulses
Author(s) -
Yi Z.G.,
Bekšić D.,
Micha D. A.
Publication year - 1997
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/(sici)1097-461x(1997)64:1<71::aid-qua8>3.0.co;2-z
Subject(s) - excited state , dissipation , chemistry , atomic physics , pulse (music) , femtosecond , substrate (aquarium) , absorption (acoustics) , time evolution , molecular physics , physics , laser , optics , quantum mechanics , oceanography , detector , geology
We describe the direct photodesorption of CO from the Ni(001) metalsurface during the absorption of a short pulse of UV light by the adsorbateand account for the dynamics of the desorbing species coupled to electronicexcitations of the substrate, which lead to energy dissipation. Theinteraction potentials and couplings for the ground and excited states areobtained from electronic structure calculations and from experimentalinformation. The time evolution of CO vibrational populations is studiedfor propagating wavepackets for the adsorbate–substrate complex witha split‐operator algorithm, followed by a perturbative treatment ofdissipation and response to the light pulse. Direct photodesorption isfound to occur predominantly in the excited electronic state and iscompatible with dissipation. Results are presented for CO photodesorptionby Gaussian pulses with several durations to show the effect of light pulseshapes on the time evolution of populations. Shorter pulses in thefemtosecond range are shown to give relatively larger populations ofexcited vibrational states during the desorption of CO. © 1997John Wiley & Sons, Inc. Int J Quant Chem 64 : 71–83,1997