The Experts below are selected from a list of 39381 Experts worldwide ranked by ideXlab platform
Joseph E Subotnik - One of the best experts on this subject based on the ideXlab platform.
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an assessment of mean field mixed semiclassical approaches equilibrium populations and algorithm stability
Journal of Chemical Physics, 2016Co-Authors: Nicole Bellonzi, Amber Jain, Joseph E SubotnikAbstract:We study several recent mean-field semiclassical dynamics methods, focusing on the ability to recover detailed balance for long time (equilibrium) populations. We focus especially on Miller and Cotton's [J. Phys. Chem. A 117, 7190 (2013)] suggestion to include both zero point Electronic Energy and windowing on top of Ehrenfest dynamics. We investigate three regimes: harmonic surfaces with weak Electronic coupling, harmonic surfaces with strong Electronic coupling, and anharmonic surfaces with weak Electronic coupling. In most cases, recent additions to Ehrenfest dynamics are a strong improvement upon mean-fieldtheory. However, for methods that include zero point Electronic Energy, we show that anharmonic potential Energy surfaces often lead to numerical instabilities, as caused by negative populations and forces. We also show that, though the effect of negative forces can appear hidden in harmonic systems, the resulting equilibrium limits do remain dependent on any windowing and zero point Energy parameters.
Nicole Bellonzi - One of the best experts on this subject based on the ideXlab platform.
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an assessment of mean field mixed semiclassical approaches equilibrium populations and algorithm stability
Journal of Chemical Physics, 2016Co-Authors: Nicole Bellonzi, Amber Jain, Joseph E SubotnikAbstract:We study several recent mean-field semiclassical dynamics methods, focusing on the ability to recover detailed balance for long time (equilibrium) populations. We focus especially on Miller and Cotton's [J. Phys. Chem. A 117, 7190 (2013)] suggestion to include both zero point Electronic Energy and windowing on top of Ehrenfest dynamics. We investigate three regimes: harmonic surfaces with weak Electronic coupling, harmonic surfaces with strong Electronic coupling, and anharmonic surfaces with weak Electronic coupling. In most cases, recent additions to Ehrenfest dynamics are a strong improvement upon mean-fieldtheory. However, for methods that include zero point Electronic Energy, we show that anharmonic potential Energy surfaces often lead to numerical instabilities, as caused by negative populations and forces. We also show that, though the effect of negative forces can appear hidden in harmonic systems, the resulting equilibrium limits do remain dependent on any windowing and zero point Energy parameters.
Amber Jain - One of the best experts on this subject based on the ideXlab platform.
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an assessment of mean field mixed semiclassical approaches equilibrium populations and algorithm stability
Journal of Chemical Physics, 2016Co-Authors: Nicole Bellonzi, Amber Jain, Joseph E SubotnikAbstract:We study several recent mean-field semiclassical dynamics methods, focusing on the ability to recover detailed balance for long time (equilibrium) populations. We focus especially on Miller and Cotton's [J. Phys. Chem. A 117, 7190 (2013)] suggestion to include both zero point Electronic Energy and windowing on top of Ehrenfest dynamics. We investigate three regimes: harmonic surfaces with weak Electronic coupling, harmonic surfaces with strong Electronic coupling, and anharmonic surfaces with weak Electronic coupling. In most cases, recent additions to Ehrenfest dynamics are a strong improvement upon mean-fieldtheory. However, for methods that include zero point Electronic Energy, we show that anharmonic potential Energy surfaces often lead to numerical instabilities, as caused by negative populations and forces. We also show that, though the effect of negative forces can appear hidden in harmonic systems, the resulting equilibrium limits do remain dependent on any windowing and zero point Energy parameters.
