Energy-resolved angular distributions and the population partition of excited state Rh atoms ejected from ion bombarded Rh [l brace]001[r brace]

Journal Article · Sat Oct 01 04:00:00 EDT 1994 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.468377· OSTI ID:7196975

He, C; Postawa, Z; El-Maazawi, M; Rosencrance, S; Garrison, B J; Winograd, N ^[1]

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1. Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

The energy-resolved angular distributions of Rh atoms ejected from Rh [l brace]001[r brace] by bombardment with 5.0 keV Ar[sup +] ions have been measured for the ground state ([ital a] [sup 4][ital F][sub 9/2]) and the two lowest lying excited state ([ital a] [sup 4][ital F][sub 7/2],[ital a] [sup 4][ital F][sub 5/2]). Simultaneous measurements on these electronic states provide us an opportunity to examine the influence of electronic interactions on desorbed particles. The experimental results show that there is a sequential variation in the angular distributions as the excitation energy increases. These variations are attributed to the interaction between the substrate electrons and the excited state atom as it is being ejected from the surface. Since the measurements are performed using multiphoton ionization via a single intermediate state, the population partition among the three lowest states is obtained as well. The excitation probabilities of the [ital a] [sup 4][ital F][sub 7/2] and [ital a] [sup 4][ital F][sub 5/2] states are compared with those predicted from the expression exp([minus][ital A]/[ital av][sub [perpendicular]]) and with a recently proposed model involving interatomic collisions above the surface. Results suggest that atoms excited via this mechanism make a significant contribution to the population of atoms ejected with low ejection velocities for the first-excited [ital a] [sup 4][ital F][sub 7/2] state (0.19 eV), as reported previously. Moreover, we suggest that an even higher proportion of atoms in the [ital a] [sup 4][ital F][sub 5/2] state are produced via this mechanism.

• OSTI ID: 7196975
• Journal Information: Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 101:7; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

665300* -- Interactions Between Beams & Condensed Matter-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANGULAR DISTRIBUTION
ARGON IONS
ATOMS
CHARGED PARTICLES
COLLISIONS
DESORPTION
DISTRIBUTION
ELEMENTS
ENERGY LEVELS
ENERGY RESOLUTION
EXCITED STATES
GROUND STATES
ION COLLISIONS
IONIZATION
IONS
METALS
MULTI-PHOTON PROCESSES
PHOTOIONIZATION
PLATINUM METALS
PROBABILITY
RESOLUTION
RHODIUM
SORPTION
SURFACES
TRANSITION ELEMENTS