The hyperfine structure of (DCCD) sub 2

Journal Article · Tue Dec 15 04:00:00 EST 1992 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.463360· OSTI ID:7028928

Bhattacharjee, R L; Muenter, J S ^[1]; Coudert, L H ^[2]

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1. Department of Chemistry, University of Rochester, Rochester, New York 14627 (United States)
2. Laboratoire de Physique Moleculaire et Applications, Boite 76, Tour 13, Universite Pierre et Marie Curie et CNRS, 4, Place Jussieu, 75252 Paris Cedex 05 (France)

An experimental and theoretical study of the quadrupole-coupling hyperfine structure of the nonrigid (C{sub 2}D{sub 2}){sub 2} dimer is carried out. This dimer exhibits a large amplitude interconversion motion which splits rotational levels into three sublevels. The quadrupole-coupling hyperfine pattern arising from the four deuterium atoms depends on the symmetry species of the tunneling sublevel. For nondegenerate sublevels, the hyperfine structure is especially interesting since the dimer behaves as if the quadrupole coupling were identical for all four deuterium atoms and the effective hyperfine Hamiltonian is completely symmetrical. The symmetry group used to classify the hyperfine levels is, therefore, the permutation group of four objects {ital S}{sub 4}. For the other tunneling sublevels, which are doubly degenerate, the dimer behaves as if the two monomer units were inequivalent. Prior to the diagonalization of the hyperfine Hamiltonian, symmetry-adapted nuclear spin wave functions in {ital S}{sub 4} are set up and allow us to select hyperfine levels whose symmetry is compatible with the tunneling symmetry species. This formalism is used to analyze the hyperfine patterns of three rovibrational transitions in (C{sub 2}D{sub 2}){sub 2}, which were recorded under high resolution. The components of effective quadrupole-coupling tensors are thereby determined. These tensors are related to the {ital eQq} of an isolated DCCD monomer to obtain vibrationally averaged angles for large amplitude bending motions within the dimer.

• DOE Contract Number: FG02-87ER60514
• OSTI ID: 7028928
• Journal Information: Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 97:12; 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
ACETYLENE
ALKYNES
DEUTERIUM
DEUTERIUM COMPOUNDS
DIMERS
ENERGY LEVELS
EXCITED STATES
HAMILTONIANS
HYDROCARBONS
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
HYPERFINE STRUCTURE
ISOTOPES
LIGHT NUCLEI
MATHEMATICAL OPERATORS
MONOMERS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
QUANTUM OPERATORS
RESOLUTION
ROTATIONAL STATES
STABLE ISOTOPES
SYMMETRY
TENSORS
TUNNEL EFFECT
VIBRATIONAL STATES