Photoionization of gas-phase bromotrifluoromethane and its complexes with methanol: State dependence of intracluster reactions

Journal Article · Mon Aug 01 00:00:00 EDT 1994 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.467714· OSTI ID:7160629

Clay, J T; Walters, E A ^[1]; Grover, J R ^[2]; Willcox, M V ^[1]

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1. Department of Chemistry and Center for Global Environmental Technologies (NMERI), University of New Mexico, Albuquerque, New Mexico 87131 (United States)
2. Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)

Weakly bound complexes of CF[sub 3]Br molecules or of CF[sub 3]Br and CH[sub 3]OH were prepared in supersonic jet expansions and studied by photoionization mass spectrometry. Argon was present in the jet expansion to promote cooling of the complexes. Measured ionization potentials are CF[sub 3]Br, 11.404[plus minus]0.014 eV; (CF[sub 3]Br)[sub 2], 11.10[plus minus]0.02 eV; (CF[sub 3]Br[center dot]CH[sub 3]OH), 10.76[plus minus]0.05 eV. The appearance potential of CF[sup +][sub 3] from CF[sub 3]Br was found to be 11.56[plus minus]0.02 eV, and evidence is presented that this value is adiabatic. From this appearance potential, [Delta][ital H][sup 0][sub [ital f]0](CF[sup +][sub 3])=86.6[plus minus]1.1 kcal mol[sup [minus]1]. The magnitude of the spin--orbit splitting in [ital [tilde X]] [sup 2][ital E] CF[sub 3]Br[sup +] into [ital E][sub 1/2] and [ital E][sub 3/2] states dominates any Jahn--Teller distortion. The effects of these phenomena on the stability of [ital [tilde X]] [sup 2][ital E] CF[sub 3]Br[sup +] are discussed. (CF[sub 3][center dot]CH[sub 3]OH)[sup +] is not produced from neutral dimers, but is created when a CF[sub 3]Br moiety embedded in a trimer or larger cluster is ionized to [ital [tilde A]] [sup 2][ital A][sub 1] CF[sub 3]Br[sup +]. In contrast, (Br[center dot]CH[sub 3]OH)[sup +] does come from dimers as well as larger clusters. The cross sections for the production of (CF[sub 3]Br)[sup +][sub 2] and (CF[sub 3]Br[center dot]CH[sub 3]OH)[sup +] from trimers or larger progenitors are enhanced when intracluster CF[sub 3]Br is ionized to CF[sub 3]Br[sup +] in the [ital [tilde B]] or higher electronic states. Possible reasons for these state-specific reactions are given. (Abstract Truncated)

• DOE Contract Number: AC02-76CH00016
• OSTI ID: 7160629
• Journal Information: Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 101:3; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

664200* -- Spectra of Atoms & Molecules & their Interactions with Photons-- (1992-)
664400 -- Experimentally Derived Information on Atomic & Molecular Properties-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ALCOHOLS
ALKANES
CHARGE EXCHANGE
CHARGED PARTICLES
CHEMISTRY
COMPLEXES
ELECTRONIC STRUCTURE
FLUID FLOW
HYDROCARBONS
HYDROXY COMPOUNDS
IONIZATION
IONS
JETS
MASS SPECTRA
METHANE
METHANOL
MOLECULAR IONS
ORGANIC BROMINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
PHOTOIONIZATION
SOLVATION
SPECTRA
STABILIZATION
SUPERSONIC FLOW