Complexes of oxygen with benzene and hexafluorobenzene

Journal Article · Wed Jul 01 04:00:00 EDT 1992 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.463559· OSTI ID:7034795

Grover, J R ^[1]; Hagenow, G ^[2]; Walters, E A ^[3]

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1. Department of Chemistry, Brookhaven National Laboratory, Upton, New York 11973 (United States)
2. Institut f uer Physikalische und Theoretische Chemie der Freien Universitaet Berlin, Takustrasse 3, D-1000 Berlin 33 (Germany)
3. Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

The complexes of C{sub 6}H{sub 6}{center dot}O{sub 2}, (C{sub 6}H{sub 6}){sub 2}O{sub 2}, and C{sub 6}F{sub 6}{center dot}O{sub 2} were studied by photoionization using synchrotron radiation. Dissociation energies were measured to be {ital D}{sub 0}(C{sub 6}H{sub 6}{center dot}O{sub 2})=1.6{plus minus}0.3 kcal mol{sup {minus}1}, {ital D}{sub 0}((C{sub 6}H{sub 6}{center dot}O{sub 2}){sup +})=3.4{plus minus}0.3 kcal mol{sup {minus}1}, {ital D}{sub 0}(C{sub 6}F{sub 6}{center dot}O{sub 2})=2.1{plus minus}0.4 kcal mol{sup {minus}1}, and {ital D}{sub 0}((C{sub 6}F{sub 6}{center dot}O{sub 2}){sup +})=3.2{plus minus}0.4 kcal mol{sup {minus}1}. We calculate from the above that {ital D}{sub 298}(C{sub 6}H{sub 6}{center dot}O{sub 2})=0.4{plus minus}0.4 kcal mol{sup {minus}1}, verifying that the benzene--oxygen interaction is only a contact'' at room temperature. The dissociation energies of the heterodimer ions are much smaller than those of the homodimer ions of their constituents (viz. 15, 11, and 7 kcal mol{sup {minus}1} for (C{sub 6}H{sub 6}){sup +}{sub 2}, (O{sub 2}){sup +}{sub 2}, and (C{sub 6}F{sub 6}){sup +}{sub 2}. ) Sharp onsets were observed for C{sub 6}H{sub 6}{center dot}O{sub 2}{r arrow}(C{sub 6}H{sub 6}{center dot}O{sub 2}){sup +} and C{sub 6}F{sub 6}{center dot}O{sub 2}{r arrow}(C{sub 6}F{sub 6}{center dot}O{sub 2}){sup +}, at 9.172{plus minus}0.004 and 9.856{plus minus}0.003 eV, respectively, measurements made possible by autoionization in the threshold region. Surprisingly, the heterodimer ion (C{sub 6}H{sub 6}{center dot}O{sub 2}){sup +} is formed essentially entirely from neutral C{sub 6}H{sub 6}{center dot}O{sub 2}, with no contribution from fragmentation of larger clusters. Production of C{sub 6}H{sub 6}O{sup +} and C{sub 6}F{sub 6}O{sup +} from C{sub 6}H{sub 6}{center dot}O{sub 2} and C{sub 6}F{sub 6}{center dot}O{sub 2} could not be detected, but is easily observed from mixed trimers.

• DOE Contract Number: AC02-76CH00016
• OSTI ID: 7034795
• Journal Information: Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 97:1; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

664500* -- Special Atoms & Molecules-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
AROMATICS
AUTOIONIZATION
BENZENE
BREMSSTRAHLUNG
CHARGE EXCHANGE
CHARGED PARTICLES
COMPLEXES
DIMERS
DISSOCIATION ENERGY
ELECTROMAGNETIC RADIATION
ENERGY
ENERGY LEVELS
EXCITED STATES
HYDROCARBONS
IONIZATION
IONS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXYGEN COMPLEXES
PHOTOIONIZATION
RADIATIONS
SYNCHROTRON RADIATION
TEMPERATURE RANGE
TEMPERATURE RANGE 0273-0400 K