TITLE

Rotational motions of CH4 molecules in weak orientational potentials of cubic symmetry

AUTHOR(S)
Asmussen, B.; Prager, M.; Press, W.; Blank, H.; Carlile, C. J.
PUB. DATE
July 1992
SOURCE
Journal of Chemical Physics;7/15/1992, Vol. 97 Issue 2, p1332
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Nearly free rotational motions of CH4 molecules as substitutional impurities in argon, krypton, and xenon have been observed at low temperatures with inelastic neutron scattering. Besides energy transfer, the dependence of the scattered intensities on momentum transfer Q is used for the assignment of the experimentally observed lines to the various transitions of a spherical quantumrotor in an orientational potential of cubic symmetry. The measured intensities are in good agreement with theoretical predictions based on the extended James–Keenan model. Measurements with high energy resolution on solid CH4 in its antiferrorotational phase II were devoted to the determination of the Q dependence of the tunneling lines and the nearly free rotor lines. The results give the first direct experimental evidence for the value 3 for the ratio of the orientationally ordered molecules to those which are orientationally disordered in CH4-II.
ACCESSION #
7639646

 

Related Articles

  • Rotational- and vibrational-state resolved HF-surface interactions investigated by surface... van Duijn, E.J.; Nokhai, R.; Hermans, L.J.F.; Pankov, A. Yu.; Krylov, S. Yu. // Journal of Chemical Physics;9/8/1997, Vol. 107 Issue 10, p3999 

    Studies the rotational and vibrational-state dependence of molecule-surface interactions. Change in accommodation coefficient for tangential momentum transfer upon excitation; Induced pressure differences; Measurement of the frequency of the laser light.

  • How do molecules move near Tg? Molecular rotation of six probes in o-terphenyl across 14 decades in time. Cicerone, Marcus T.; Blackburn, F. R.; Ediger, M. D. // Journal of Chemical Physics;1/1/1995, Vol. 102 Issue 1, p471 

    Time resolved optical spectroscopy was used to observe molecular rotation over more than 14 decades in time for six probes in o-terphenyl (OTP). In contrast to previous studies, probe rotation times are found to depend significantly upon probe size in the deeply supercooled regime. Systematic...

  • Rotational optical activity. Polavarapu, P. L. // Journal of Chemical Physics;2/1/1987, Vol. 86 Issue 3, p1136 

    Optical activity generated by the rotational normal coordinates is investigated. The theoretical formulation is based on classical principles and uses the definition of the rotational normal coordinates and the changes in electric and magnetic dipole moment components along the principal axes of...

  • Rotation–vibration spectra of icosahedral molecules. II. Icosahedral symmetry, vibrational eigenfrequencies, and normal modes of buckminsterfullerene. Weeks, David E.; Harter, William G. // Journal of Chemical Physics;5/1/1989, Vol. 90 Issue 9, p4744 

    The icosahedral symmetry of molecules such as buckyball, B12H12-2, and C20H20, is analyzed using subgroup chain defined projection operators. The icosahedral analysis is used to determine the eigenvalues and eigenvectors of a classical spring mass model of buckyball. A spectrum of Raman and...

  • Rotation–vibration spectra of icosahedral molecules. I. Icosahedral symmetry analysis and fine structure. Harter, William G.; Weeks, David E. // Journal of Chemical Physics;5/1/1989, Vol. 90 Issue 9, p4727 

    Icosahedral symmetry analysis is developed for analyzing eigensolutions of rovibrational tensor Hamiltonians for molecules such as B12H12-2, C20H20, and C60. Simplified asymptotic formulas and procedures are developed for obtaining rotational spectral fine structure for high angular momentum....

  • Rotational spectra and hyperfine constants of ZrO and ZrS. Beaton, Sara A.; Gerry, Michael C. L. // Journal of Chemical Physics;6/8/1999, Vol. 110 Issue 22, p10715 

    Studies the rotational spectra and hyperfine constants of molecules considered to be astrophysical importance using the cavity pulsed Fourier transform microwave (FTMW) spectroscopy. Detection of transition metal oxides and hydrides through electronic spectra in cool, carbon rich stars;...

  • Energy migration and rotational motion within bichromophoric molecules. II. A derivation of the fluorescence anisotropy. Johansson, L. B.-Å.; Edman, Peter; Westlund, P.-O. // Journal of Chemical Physics;12/22/1996, Vol. 105 Issue 24, p10896 

    A generalized Förster theory is presented which includes reorientation of the interacting molecules. The stochastic master equation is, for the first time, derived from the stochastic Liouville equation, so that it accounts for the molecular origin to the stochastic transitions rates. A...

  • Unidirectional rotary motion in a molecular system. Kelly, T. Ross; De Silva, Harshani // Nature;9/9/1999, Vol. 401 Issue 6749, p150 

    Investigates a molecule that uses chemical energy to activate and achieve unidirectional intramolecular rotary motion. Triptycene and helicene components of the structure; Use of the chemical energy of carbonyl dichloride to induce movement to the molecule.

  • Influence of rotational states on molecular multiphoton excitation. Chang, Johnny; Wyatt, Robert E. // Journal of Chemical Physics;8/15/1986, Vol. 85 Issue 4, p1840 

    The role of rotational states in IR multiphoton excitation (MPE) is examined for a model spherical top molecule. While the common belief that inclusion of rotational states can enhance MPE by overcoming anharmonic detunings and increasing the number of pathways for excitation is correct for some...

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics