skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Charge-transfer rates for xenon Rydberg atoms at a metal surface

Abstract

The ionization of xenon Rydberg atoms excited to the lowest states in the n=17 and n=20 Stark manifolds at a flat Au(111) surface is investigated. Despite the strong perturbations in the energies and structure of the atomic states that occur as the surface is approached, it is shown that, under appropriate conditions, each incident atom can be detected as an ion and that the experimental data can be well fit by assuming that the ionization rate on average increases exponentially as the surface is approached. The ionization rates are compared to theoretical predictions.

Authors:
 [1]; ; ;  [2]
  1. Institut fuer Physik der Humboldt-Universitaet zu Berlin, Newtonstr. 15, D-12489 Berlin (Germany)
  2. Department of Physics and Astronomy and the Rice Quantum Institute, Rice University, MS-61, 6100 Main Street, Houston, Texas 77005-1892 (United States)
Publication Date:
OSTI Identifier:
20786934
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 73; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevA.73.032903; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ATOMS; CHARGE EXCHANGE; DISTURBANCES; GOLD; IONIZATION; IONS; RYDBERG STATES; SURFACES; XENON

Citation Formats

Wethekam, S., Dunham, H. R., Lancaster, J. C., and Dunning, F. B.. Charge-transfer rates for xenon Rydberg atoms at a metal surface. United States: N. p., 2006. Web. doi:10.1103/PHYSREVA.73.0.
Wethekam, S., Dunham, H. R., Lancaster, J. C., & Dunning, F. B.. Charge-transfer rates for xenon Rydberg atoms at a metal surface. United States. doi:10.1103/PHYSREVA.73.0.
Wethekam, S., Dunham, H. R., Lancaster, J. C., and Dunning, F. B.. Wed . "Charge-transfer rates for xenon Rydberg atoms at a metal surface". United States. doi:10.1103/PHYSREVA.73.0.
@article{osti_20786934,
title = {Charge-transfer rates for xenon Rydberg atoms at a metal surface},
author = {Wethekam, S. and Dunham, H. R. and Lancaster, J. C. and Dunning, F. B.},
abstractNote = {The ionization of xenon Rydberg atoms excited to the lowest states in the n=17 and n=20 Stark manifolds at a flat Au(111) surface is investigated. Despite the strong perturbations in the energies and structure of the atomic states that occur as the surface is approached, it is shown that, under appropriate conditions, each incident atom can be detected as an ion and that the experimental data can be well fit by assuming that the ionization rate on average increases exponentially as the surface is approached. The ionization rates are compared to theoretical predictions.},
doi = {10.1103/PHYSREVA.73.0},
journal = {Physical Review. A},
number = 3,
volume = 73,
place = {United States},
year = {Wed Mar 15 00:00:00 EST 2006},
month = {Wed Mar 15 00:00:00 EST 2006}
}
  • Electron transfer and the production of negative hydrogen ions in the reflection of hydrogen atoms from a metal surface is studied theoretically. Starting from the total Hamiltonian of the metal--atom system, the time development of the one-electron density matrix is determined. This is shown to be related to the time-dependent coupling of the affinity level of the moving atom with the metal states. In the limit of weak coupling, the occupation probability of the affinity level can be obtained in a closed form. This theory is applied to the problem of negative hydrogen ion production at a W(110) surface, bothmore » with and without Cs coverage, and the results are compared with available experimental data and predictions of existing theories.« less
  • The modification of cerium dioxide with nanoscale metal clusters is intensely researched for catalysis applications, with gold, silver, and copper having been particularly well studied. The interaction of the metal cluster with ceria is driven principally by a localised interaction between a small number of metal atoms (as small as one) and the surface and understanding the fundamentals of the interaction of metal atoms with ceria surfaces is therefore of great interest. Much attention has been focused on the interaction of metals with the (111) surface of ceria, since this is the most stable surface and can be grown asmore » films, which are probed experimentally. However, nanostructures exposing other surfaces such as (110) show high activity for reactions including CO oxidation and require further study; these nanostructures could be modified by deposition of metal atoms or small clusters, but there is no information to date on the atomic level details of metal-ceria interactions involving the (110) surface. This paper presents the results of density functional theory (DFT) corrected for on-site Coulomb interactions (DFT+U) calculations of the adsorption of a number of different metal atoms at an extended ceria (110) surface; the metals are Au, Ag, Cu, Al, Ga, In, La, Ce, V, Cr, and Fe. Upon adsorption all metals are oxidised, transferring electron(s) to the surface, resulting in localised surface distortions. The precise details depend on the identity of the metal atom. Au, Ag, Cu each transfer one electron to the surface, reducing one Ce ion to Ce{sup 3+}, while of the trivalent metals, Al and La are fully oxidised, but Ga and In are only partially oxidised. Ce and the transition metals are also partially oxidised, with the number of reduced Ce ions possible in this surface no more than three per adsorbed metal atom. The predicted oxidation states of the adsorbed metal atoms should be testable in experiments on ceria nanostructures modified with metal atoms.« less
  • A highly excited (Rydberg) atom bathed in blackbody radiation is perturbed in two ways. A dynamic Stark shift is induced by the off-resonant components of the blackbody radiation. Additionally, electric-dipole transitions to other atomic energy levels are induced by the resonant components of the blackbody radiation. This depopulation effect shortens the Rydberg-state lifetime, thereby broadening the energy level. Calculations of these two effects in many states of hydrogen, helium, and the alkali-metal atoms Li, Na, K, Rb, and Cs are presented for T = 300 K. Contributions from the entire blackbody spectrum and from both discrete and continuous perturbing statesmore » are included. The accuracy is considerably greater than that of previous estimates.« less
  • Rates of depopulation by blackbody radiation (BBR) and effective lifetimes of alkali-metal nS, nP, and nD Rydberg states have been calculated in a wide range of principal quantum numbers n{<=}80 at the ambient temperatures of 77, 300, and 600 K. Quasiclassical formulas were used to calculate the radial matrix elements of the dipole transitions from Rydberg states. Good agreement of our numerical results with the available theoretical and experimental data has been found. We have also obtained simple analytical formulas for estimates of effective lifetimes and BBR-induced depopulation rates, which well agree with the numerical data.