title: Internal rotation and spin conversion of CH3OH in solid para-hydrogen.
abstract: The quantum solid para-hydrogen (p-H2) has recently proven useful in matrix isolation spectroscopy. Spectral lines of compounds embedded in this host are unusually narrow, and several species have been reported to rotate in p-H2. We found that a p-H2 matrix inhibits rotation of isolated methanol (CH3OH) but still allows internal rotation about the C-O bond, with splittings of the E/A torsional doublet in internal rotation-coupled vibrational modes that are qualitatively consistent with those for CH3OH in the gaseous phase. This simplified high-resolution spectrum further revealed the slow conversion of nuclear spin symmetry from species E to species A in the host matrix, offering potential insight into nuclear spin conversion in astrophysical sources.
authors.affiliation: Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, 1001 Ta-Hsueh Road, Hsinchu 30010, Taiwan. yplee@mail.nctu.edu.tw
authors.forename: Yuan-Pern
authors.initials: YP
authors.lastname: Lee
authors.forename: Yu-Jong
authors.initials: YJ
authors.lastname: Wu
authors.forename: R M
authors.initials: RM
authors.lastname: Lees
authors.forename: Li-Hong
authors.initials: LH
authors.lastname: Xu
authors.forename: Jon T
authors.initials: JT
authors.lastname: Hougen