Theoretical and neon matrix electron spin resonance studies of the methanol cation: CH sub 3 OH sup + , CH sub 3 OD sup + , CH sub 2 DOH sup + , and sup 13 CH sub 3 OH sup +

Journal Article · Thu Oct 15 00:00:00 EDT 1992 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.463796· OSTI ID:7252437

Knight, Jr, L B; Kerr, K; Villanueva, M; McKinley, A J ^[1]; Feller, D ^[2]

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1. Department of Chemistry, Furman University, Greenville, South Carolina 29613 (United States)
2. Molecular Science Research Center, Pacific Northwest Laboratory, Richland, Washington 99352 (United States)

Four isotopes of the methanol cation radical (CH{sub 3}OH{sup +}) have been generated by three independent methods and isolated in neon matrices at 4 K for a detailed electron spin resonance (ESR) investigation. The ion generation methods employed were {ital X} irradiation, photoionization, and electron ionization. The nuclear hyperfine ({ital A} tensors) measurements were compared with those obtained from {ital ab} {ital initio} extended basis set multireference configuration interaction (CI) wave functions. The relationships between geometry and electronic structures were fully explored. The trend in the large isotropic methyl hydrogen {ital A} values for the isoelectronic series CH{sub 3}F{sup +}, CH{sub 3}OH{sup +}, and CH{sub 3}NH{sub 2{sup +}} was found to follow the trend in dissociation energies for these radical cations. The neon magnetic parameters for CH{sub 3}OH{sup +} are {ital g}{sub {ital x}}=2.0036(4) and {ital g}{sub {ital z}}=2.010(1); {ital A}{sub iso} (methyl hydrogens)=229(1) MHz, {vert bar}{ital A}{sub {ital x}}{vert bar}=54(2) and {vert bar}{ital A}{sub {ital z}}{vert bar}=80(3) MHz for the hydroxy hydrogen; {vert bar}{ital A}{sub {ital x}}{vert bar}=40(2) and {vert bar}{ital A}{sub {ital z}}{vert bar}=29(4) MHz for {sup 13}C. The observed magnetic parameters for CH{sub 2}DOH{sup +} indicate an unusually large deuterium effect {ital A}{sub iso} (CH{sub 2})=329 MHz with {vert bar}{ital A}{sub iso}{vert bar}=4.1(3) MHz for the methyl deuterium. These results show that averaging of the methyl hydrogen environments is occurring on the ESR time scale.

• DOE Contract Number: AC06-76RL01830
• OSTI ID: 7252437
• Journal Information: Journal of Chemical Physics; (United States), Vol. 97:8; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
CATIONS
ELECTRONIC STRUCTURE
GEOMETRY
METHANOL
CARBON 13
CONFIGURATION INTERACTION
ELECTRON SPIN RESONANCE
ISOTOPES
MATRIX ISOLATION
NEON
RADICALS
TEMPERATURE RANGE 0000-0013 K
ALCOHOLS
CARBON ISOTOPES
CHARGED PARTICLES
ELEMENTS
EVEN-ODD NUCLEI
FLUIDS
GASES
HYDROXY COMPOUNDS
IONS
LIGHT NUCLEI
MAGNETIC RESONANCE
MATHEMATICS
NONMETALS
NUCLEI
ORGANIC COMPOUNDS
RARE GASES
RESONANCE
STABLE ISOTOPES
TEMPERATURE RANGE
664400* - Experimentally Derived Information on Atomic & Molecular Properties- (1992-)
664100 - Theory of Electronic Structure of Atoms & Molecules- (1992-)