Vibrational Relaxation

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Ilan Benjamin - One of the best experts on this subject based on the ideXlab platform.

  • Photodissociation and Vibrational Relaxation of OClO at Liquid Surfaces
    The Journal of Physical Chemistry B, 2003
    Co-Authors: Ilya Chorny, John Vieceli, Ilan Benjamin
    Abstract:

    The photodissociation dynamics of OClO to O + ClO on the 2A2 excited state and the Vibrational Relaxation of OClO in the ground electronic state at the interface of several polar liquids are studied using classical molecular dynamics computer simulations. The results are compared with recent calculations and experiments of photodissociation and Vibrational Relaxation of OClO in bulk water, acetonitrile, and ethanol. In contrast with substantial geminate recombination in the bulk, the photodissociation at the liquid/vapor interface of all three liquids gives rise to nearly 100% cage escape. In most of the trajectories at least one of the dissociation fragments desorb, although a significant percentage of the ClO fragments remain adsorbed at the interface. The reduced density at the interface gives rise to reduced friction and to slower Vibrational Relaxation of ground-state OClO (which may form as a result of geminate recombination of the photofragments). The Vibrational Relaxation of ground-state OClO is ...

  • Vibrational Relaxation at water surfaces
    The Journal of Chemical Physics, 2002
    Co-Authors: John Vieceli, Ilya Chorny, Ilan Benjamin
    Abstract:

    The Vibrational Relaxation of several diatomic molecules at the surface of liquid water is studied using classical molecular-dynamics computer simulations and compared with the same process in the bulk liquids. Both nonequilibrium classical trajectory calculations and equilibrium force autocorrleation functions are used to elucidate the factors that influence Vibrational energy Relaxation at the liquid surface region. We find that in general Vibrational Relaxation rates at interfaces are slower than in the bulk due to reduced friction. However, the degree of the slowing-down effect depends on the contribution of electrostatic forces and is correlated with the structure of the first solvation shell.

Ward H. Thompson - One of the best experts on this subject based on the ideXlab platform.

  • Simulations of the Vibrational Relaxation of I2 in Xe
    The Journal of Physical Chemistry A, 2003
    Co-Authors: Ward H. Thompson
    Abstract:

    The Vibrational Relaxation of an I2 molecule in a xenon fluid has been simulated by three methods. The conventional perturbation theory approach based on an equilibrium molecular dynamics (MD) simulation is compared with purely classical nonequilibrium MD and mixed quantum−classical surface-hopping MD simulations. Relaxation times and state-to-state Vibrational transition rate constants obtained with these three approaches are compared and information that can be extracted concerning the mechanism of Vibrational Relaxation is examined. Both harmonic and anharmonic solutes are considered as are some common approximations invoked in obtaining Vibrational Relaxation times.

Brian S. Wherrett - One of the best experts on this subject based on the ideXlab platform.

  • Measurement of the Vibrational Relaxation time in metal-phthalocyanine solutions
    Optical Materials, 1997
    Co-Authors: Raul Rangel-rojo, G. Spruce, Brian S. Wherrett
    Abstract:

    Abstract We report degenerate subpicosecond excite-probe experiments at a wavelength close to the absorption peak of an excited Vibrational state of two different metalphthalocyanine solutions. By using this technique, we were able to resolve in time the Vibrational Relaxation within the first electronic excited state of the molecule. A four-level model is used to explain the observed nonlinear response. Theoretical modeling allows us to obtain both the Vibrational Relaxation time, and two different excited-state absorption cross-sections for each of the samples studied.

A.z. Gadzhiev - One of the best experts on this subject based on the ideXlab platform.

  • Raman spectra and Vibrational Relaxation in molten thiocyanates
    Journal of Molecular Liquids, 2003
    Co-Authors: A.r. Aliev, A.z. Gadzhiev
    Abstract:

    Abstract Temperature measurements of Raman spectra of thiocyanates of alkali metals in the interval from Tmelt to Tmelt + 100 K are carried out. A method of correlation functions (CF) is discussed which allows one to apply for the analysis the intensity distribution over the whole band contour and which associates the experimental spectrum with the molecular motion characteristics. CF of Vibrational Relaxation are calculated. It is shown that the main mechanism of the Vibrational Relaxation and, consequently, the reason of broadening of isotropic components in Raman spectra of ionic melts is the phase Relaxation process as a result of frequent quasi-elastic collisions of ions.

John Vieceli - One of the best experts on this subject based on the ideXlab platform.

  • Photodissociation and Vibrational Relaxation of OClO at Liquid Surfaces
    The Journal of Physical Chemistry B, 2003
    Co-Authors: Ilya Chorny, John Vieceli, Ilan Benjamin
    Abstract:

    The photodissociation dynamics of OClO to O + ClO on the 2A2 excited state and the Vibrational Relaxation of OClO in the ground electronic state at the interface of several polar liquids are studied using classical molecular dynamics computer simulations. The results are compared with recent calculations and experiments of photodissociation and Vibrational Relaxation of OClO in bulk water, acetonitrile, and ethanol. In contrast with substantial geminate recombination in the bulk, the photodissociation at the liquid/vapor interface of all three liquids gives rise to nearly 100% cage escape. In most of the trajectories at least one of the dissociation fragments desorb, although a significant percentage of the ClO fragments remain adsorbed at the interface. The reduced density at the interface gives rise to reduced friction and to slower Vibrational Relaxation of ground-state OClO (which may form as a result of geminate recombination of the photofragments). The Vibrational Relaxation of ground-state OClO is ...

  • Vibrational Relaxation at water surfaces
    The Journal of Chemical Physics, 2002
    Co-Authors: John Vieceli, Ilya Chorny, Ilan Benjamin
    Abstract:

    The Vibrational Relaxation of several diatomic molecules at the surface of liquid water is studied using classical molecular-dynamics computer simulations and compared with the same process in the bulk liquids. Both nonequilibrium classical trajectory calculations and equilibrium force autocorrleation functions are used to elucidate the factors that influence Vibrational energy Relaxation at the liquid surface region. We find that in general Vibrational Relaxation rates at interfaces are slower than in the bulk due to reduced friction. However, the degree of the slowing-down effect depends on the contribution of electrostatic forces and is correlated with the structure of the first solvation shell.