Angular momentum dependent friction slows down rotational relaxation under nonequilibrium conditions

Gelin, M F; Kosov, D S

doi:10.1063/1.2401609

Title: Angular momentum dependent friction slows down rotational relaxation under nonequilibrium conditions

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Abstract

It has recently been shown that relaxation of the rotational energy of hot nonequilibrium photofragments (i) slows down significantly with the increase of their initial rotational temperature and (ii) differs dramatically from the relaxation of the equilibrium rotational energy correlation function, manifesting thereby the breakdown of the linear response description [A. C. Moskun et al., Science 311, 1907 (2006)]. We demonstrate that this phenomenon may be caused by the angular momentum dependence of rotational friction. We have developed the generalized Fokker-Planck equation whose rotational friction depends upon angular momentum algebraically. The calculated rotational correlation functions correspond well to their counterparts obtained via molecular dynamics simulations in a broad range of initial nonequilibrium conditions. It is suggested that the angular momentum dependence of friction should be taken into account while describing rotational relaxation far from equilibrium.

Authors:

Gelin, M F; Kosov, D S ^[1]

Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742 (United States)

Publication Date:: Thu Dec 14 00:00:00 EST 2006

OSTI Identifier:: 20864355

Resource Type:: Journal Article

Journal Name:: Journal of Chemical Physics

Additional Journal Information:: Journal Volume: 125; Journal Issue: 22; Other Information: DOI: 10.1063/1.2401609; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606

Country of Publication:: United States

Language:: English

Subject:: 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANGULAR MOMENTUM; CORRELATION FUNCTIONS; DISSOCIATION; FOKKER-PLANCK EQUATION; MOLECULAR DYNAMICS METHOD; PHOTOLYSIS; RELAXATION; ROTATIONAL STATES; SIMULATION

Citation Formats


                    Gelin, M F, and Kosov, D S. Angular momentum dependent friction slows down rotational relaxation under nonequilibrium conditions.  United States: N. p., 2006. 
        Web.  doi:10.1063/1.2401609.

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                    Gelin, M F, & Kosov, D S. Angular momentum dependent friction slows down rotational relaxation under nonequilibrium conditions.  United States.  https://doi.org/10.1063/1.2401609

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                    Gelin, M F, and Kosov, D S. 2006.  
        "Angular momentum dependent friction slows down rotational relaxation under nonequilibrium conditions".  United States.  https://doi.org/10.1063/1.2401609.

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@article{osti_20864355,

  title        = {Angular momentum dependent friction slows down rotational relaxation under nonequilibrium conditions},

  author       = {Gelin, M F and Kosov, D S},

  abstractNote = {It has recently been shown that relaxation of the rotational energy of hot nonequilibrium photofragments (i) slows down significantly with the increase of their initial rotational temperature and (ii) differs dramatically from the relaxation of the equilibrium rotational energy correlation function, manifesting thereby the breakdown of the linear response description [A. C. Moskun et al., Science 311, 1907 (2006)]. We demonstrate that this phenomenon may be caused by the angular momentum dependence of rotational friction. We have developed the generalized Fokker-Planck equation whose rotational friction depends upon angular momentum algebraically. The calculated rotational correlation functions correspond well to their counterparts obtained via molecular dynamics simulations in a broad range of initial nonequilibrium conditions. It is suggested that the angular momentum dependence of friction should be taken into account while describing rotational relaxation far from equilibrium.},

  doi          = {10.1063/1.2401609},

  url          = {https://www.osti.gov/biblio/20864355},
  journal      = {Journal of Chemical Physics},

  issn         = {0021-9606},

  number       = 22,

  volume       = 125,

  place        = {United States},

  year         = {Thu Dec 14 00:00:00 EST 2006},

  month        = {Thu Dec 14 00:00:00 EST 2006}

}

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