Abstract
Electronic excitations in adsorbate layers stimulate desorption and dissociation of adsorbed molecules as well as chemical reactions between adsorbates. The highest-probability stimulated processes produce neutral desorbates and determine how surface composition is altered by electron or photon radiation. A basic understanding has emerged, due largely to laser resonance-enhanced multi-photon ionization (REMPI) experiments, which provide quantum-state resolution of the gas-phase products. Auger phenomena enter this understanding in several ways. For example, CVV Auger spectroscopy determines the screened hole-hole interaction, U, in adsorbates, which in turn provides insight into the degree of charge-transfer screening from the substrate. In those systems where screening charge is used in excitation Auger decay, screening directly determines the lifetime, which in turn can exponentially affect the yield. Reductions in screening, e.g. induced by coadsorption of electro-negative species, thus can result in giant yield enhancements. As separate issues, a finite U may prevent the fast resonant decay and thus increase the yield from two-hole excitations, as has been suggested for NO2 dissociation on Pt(lll), or may assist in the localization (self-trapping) of two-hole excitations in dense adsorbate layers, as apparently is the case for NO desorption from the same surface. The latter causes the yields from one- and two-hole excitations to differ in their coverage dependence. Finally, CVV Auger spectroscopy, of course, measures the energies of two-hole excitations, which can be correlated with observed stimulated thresholds.
| Original language | English |
|---|---|
| Pages (from-to) | 36 |
| Number of pages | 1 |
| Journal | Physica Scripta |
| Volume | 1992 |
| Issue number | T41 |
| DOIs | |
| Publication status | Published - Jan 1 1992 |
Fingerprint
ASJC Scopus subject areas
- Condensed Matter Physics
- Mathematical Physics
- Atomic and Molecular Physics, and Optics
Cite this
Auger spectroscopy and electronically-stimulated surface processes. / Jennison, D. R.; Burns, A. R.; Stechel, Ellen.
In: Physica Scripta, Vol. 1992, No. T41, 01.01.1992, p. 36.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Auger spectroscopy and electronically-stimulated surface processes
AU - Jennison, D. R.
AU - Burns, A. R.
AU - Stechel, Ellen
PY - 1992/1/1
Y1 - 1992/1/1
N2 - Electronic excitations in adsorbate layers stimulate desorption and dissociation of adsorbed molecules as well as chemical reactions between adsorbates. The highest-probability stimulated processes produce neutral desorbates and determine how surface composition is altered by electron or photon radiation. A basic understanding has emerged, due largely to laser resonance-enhanced multi-photon ionization (REMPI) experiments, which provide quantum-state resolution of the gas-phase products. Auger phenomena enter this understanding in several ways. For example, CVV Auger spectroscopy determines the screened hole-hole interaction, U, in adsorbates, which in turn provides insight into the degree of charge-transfer screening from the substrate. In those systems where screening charge is used in excitation Auger decay, screening directly determines the lifetime, which in turn can exponentially affect the yield. Reductions in screening, e.g. induced by coadsorption of electro-negative species, thus can result in giant yield enhancements. As separate issues, a finite U may prevent the fast resonant decay and thus increase the yield from two-hole excitations, as has been suggested for NO2 dissociation on Pt(lll), or may assist in the localization (self-trapping) of two-hole excitations in dense adsorbate layers, as apparently is the case for NO desorption from the same surface. The latter causes the yields from one- and two-hole excitations to differ in their coverage dependence. Finally, CVV Auger spectroscopy, of course, measures the energies of two-hole excitations, which can be correlated with observed stimulated thresholds.
AB - Electronic excitations in adsorbate layers stimulate desorption and dissociation of adsorbed molecules as well as chemical reactions between adsorbates. The highest-probability stimulated processes produce neutral desorbates and determine how surface composition is altered by electron or photon radiation. A basic understanding has emerged, due largely to laser resonance-enhanced multi-photon ionization (REMPI) experiments, which provide quantum-state resolution of the gas-phase products. Auger phenomena enter this understanding in several ways. For example, CVV Auger spectroscopy determines the screened hole-hole interaction, U, in adsorbates, which in turn provides insight into the degree of charge-transfer screening from the substrate. In those systems where screening charge is used in excitation Auger decay, screening directly determines the lifetime, which in turn can exponentially affect the yield. Reductions in screening, e.g. induced by coadsorption of electro-negative species, thus can result in giant yield enhancements. As separate issues, a finite U may prevent the fast resonant decay and thus increase the yield from two-hole excitations, as has been suggested for NO2 dissociation on Pt(lll), or may assist in the localization (self-trapping) of two-hole excitations in dense adsorbate layers, as apparently is the case for NO desorption from the same surface. The latter causes the yields from one- and two-hole excitations to differ in their coverage dependence. Finally, CVV Auger spectroscopy, of course, measures the energies of two-hole excitations, which can be correlated with observed stimulated thresholds.
UR - http://www.scopus.com/inward/record.url?scp=0041510472&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0041510472&partnerID=8YFLogxK
U2 - 10.1088/0031-8949/1992/T41/006
DO - 10.1088/0031-8949/1992/T41/006
M3 - Article
AN - SCOPUS:0041510472
VL - 1992
SP - 36
JO - Physica Scripta
JF - Physica Scripta
SN - 0031-8949
IS - T41
ER -