Faculty Publications

Molecular Photofragmentation During Non-resonant Multiphoton Ionization of Sputtered Species

Document Type

Article

Journal/Book/Conference Title

Surface and Interface Analysis

Volume

20

Issue

12

First Page

1007

Last Page

1010

Abstract

To assess the quantitative analytical capabilities of laser post‐ionization of sputtered neutrals, the photoionization of sputtered Cu, Al and Ru atoms and clusters was investigated. By measuring velocity distributions using both resonant and non‐resonant photoionization of the atoms and one‐photon and two‐photon ionization of the clusters, photogragmentation of clusters was found to be significant. Atomic velocity distributions measured using non‐resonant ionization peaked at the same velocity as the respective dimer distribution, indicating that the majority of the non‐resonant atomic ion signal is from photogragmented dimers. The contribution to the dimer ion signal from photogragmentation of the trimer varied with the two‐photon laser power density. Domination of the atomic photoion channel by molecule fragmentation appears to be a general phenomenon that must be accounted for in all gas‐phase multiphoton non‐resonant ionization experiments at easily achievable laser power densities (≤ 108 W cm−2). To minize photogragmentation effects, atoms should be ionized resonantly and clusters should be onephoton ionized. Copyright © 1993 John Wiley & Sons Ltd.

Department

Department of Chemistry and Biochemistry

Original Publication Date

1-1-1993

DOI of published version

10.1002/sia.740201212

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