Award Date

1-1-2001

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

First Committee Member

Dennis W. Lindle

Number of Pages

62

Abstract

Mass spectroscopy is used to study the formation of cations and anions after photoexcitation and photoionization of OCS in the vicinity of the S 2p, C 1s and O 1s thresholds. Singly charged cations are produced predominantly at the pi* and Rydberg resonances while dications are major products of dissociative channels above the thresholds. At the S 2p threshold, broad Franck-Condon regions observed for Rydberg excited states manifests an apparent change in molecular bond lengths upon the excitation of S 2p electrons to Rydberg orbitals. Neutral dissociation of the pi*3/2, pi*1/2 and 4S 3/2 excited states is found to compete efficiently with electronic relaxation via Auger processes. The observation of SO+ ions at the pi* resonance indicates a strong Renner-Teller vibronic coupling of bending vibrations in the 4pi* excited states with a bent equilibrium geometry. The anions (S-, C- and O-) are observed both below and above the thresholds. The fact that the anion production is suppressed at shape resonances allows the anions to serve as a suggestive and complementary tool for identifying above-threshold structures in the OCS photoabsorption spectra. Post-collision-interaction effects in OCS and locality of the lowest unoccupied molecular orbital 4pi* at the sulfur atom are also evidenced in the anion spectra.

Keywords

Carbonyl; Core; Following; Ocs; Photoexcitation; Photofragmentation; Photoionization; Shell; Sulfide

Controlled Subject

Chemistry, Physical and theoretical; Molecular dynamics

File Format

pdf

File Size

1566.72 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

Permissions

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Identifier

https://doi.org/10.25669/x2yn-kmkx


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