Laser Control of Desorption Through Selective Surface Excitation
We review recent developments in controlling photo-induced desorption processes of alkali halides and magnesium oxide. We focus primarily on hyperthermal desorption of halogen (and oxygen) atoms and show that the yield, electronic state, and velocity distributions of desorbed atoms can be selected using tunable laser excitation. We demonstrate that the observed control is due to preferential excitation of surface excitons. This approach takes advantage of energetic differences between surface and bulk exciton states and probes the surface exciton directly. We demonstrate that desorption of these materials leads to controlled modification of their surface geometric and electronic structures. Laser desorption can serve as a solid-state source of halogen and oxygen atoms in well defined electronic states and with controlled velocity distributions. The latter can be used for studying chemical processes in the gas phase and at surfaces. We demonstrate that the exciton mechanism of desorption developed for alkali halides can be extended to cubic oxide surfaces.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 876928
- Report Number(s):
- PNNL-SA-45473; JPCBFK; 4792; KC0301020; TRN: US0601451
- Journal Information:
- Journal of Physical Chemistry B, 109(42):19563-19578, Vol. 109, Issue 42; ISSN 1089-5647
- Country of Publication:
- United States
- Language:
- English
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