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), Journal Name: Journal of Chemical Physics; (United States) Vol. 97:8; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

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