Chemisorbed-molecule potential-energy surfaces and electronically stimulated processes

Dwight R. Jennison, Ellen B. Stechel, Alan R. Burns, Y. S. Li

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Three topics illustrate some central physics of processes produced by UV-laser and low-energy electron stimulation. First, a multi-dimensional ground-state potential energy surface (PES) for NH3:Pd(111), computed using ab initio local-density functional theory, allows dramatically different dynamics depending on poorly-known excited-state forces. We use quantum-resolved experimental data to argue that stimulated desorption is dominated by a direct path off the surface, following placement of the wavepacket on a molecule-surface hard wall accessed by internal molecular motion. This illustrates the questionable relevance of 1D models for understanding molecule-surface dynamics. Second, we study the image-charge model of excited state forces experienced by ions produced, for example, by hot carrier attachment. Ab initio results show that this model totally fails at molecule-surface distances typical of chemisorption. Finally, we present a purely-electronic adiabatic model of excited state PESs and use it to argue that, if significant covalent interactions occur between an adsorbate and a surface, hot carrier attachment does not simply produce singly- charged ions. Instead, attachment creates excitation of the molecule-surface bond occur and, in some cases, may result in multiply-charged ions.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsHai-Lung Dai, Steven J. Sibener
PublisherSociety of Photo-Optical Instrumentation Engineers
Number of pages15
ISBN (Print)0819414182
StatePublished - 1994
Externally publishedYes
EventLaser Techniques for Surface Science - Los Angeles, CA, USA
Duration: Jan 27 1994Jan 29 1994

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherLaser Techniques for Surface Science
CityLos Angeles, CA, USA

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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