Energy and capacity time correlation functions for investigation of vibrational energy relaxation

Schwarzer, Dirk; Vikhrenko, D. V.; Vikhrenko, V. S.

doi:10.1016/j.chemphys.2004.02.001

Cited by 6 publications

(4 citation statements)

References 54 publications

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“…The key point is that this friction kernel form was later used to study vibrational relaxation of diatomics with physically reasonable results. 55,69 We now turn to its parametrization. The function eq 11 oscillates with the period τ = (2π/Rδ) and reaches zero at t = (π/2Rδ).…”

Section: Friction Kernels Description and Parametrizationmentioning

confidence: 99%

“…For this purpose, we employ the friction kernel functional form initially proposed by Douglass (as a velocity tcf) , ζ ( t ) = ζ 0 cos ( α δ t ) cosh ( α t ) It is more complex than a Gaussian and has three parameters (ζ 0 setting the initial value; α controlling the decay time scale; and δ defining the shape/oscillatory behavior). The key point is that this friction kernel form was later used to study vibrational relaxation of diatomics with physically reasonable results. , We now turn to its parametrization.…”

Section: Inclusion Of Dissipative Effects For the Psb And The Solventmentioning

confidence: 99%

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Dynamical Friction Effects on the Photoisomerization of a Model Protonated Schiff Base in Solution

2010

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Photoisomerization involving a conical intersection (CI) for a model protonated Schiff base (PSB) in modeled water and acetonitrile solvents is examined with the inclusion of energy- and momentum-transfer effects described via a generalized Langevin equation (GLE) frictional approach and surface-hopping dynamics. Short-time GLE frictional effects on the model's three coordinates, the intramolecular bond length alternation and torsional PSB coordinates and a solvent coordinate, eliminate several unphysical features associated with a no-friction inertial description and have the general feature of accelerating nonadiabatic transitions to the ground electronic state. The inertial prediction of equal probability formation of ground-state trans and cis isomer products subsequent to the Franck-Condon excitation of the ground cis isomer is replaced by the GLE prediction of a preferential higher proportion of ground-state trans isomer, that is, a successful cis to trans photoreaction. This preference is solvent-dependent and is enhanced in water solvent with its higher friction intensity and short time scales. For the fast water solvent motion, the nonadiabatic transitions to the S(0) ground state are centered around the CI seam (which is due to the solvent coordinate's role as a tuning coordinate), facilitating direct transitions to the ground-state trans isomer. In contrast, for the slower acetonitrile solvent motion, the decay occurs, on average, away from the CI seam in regions with a finite free-energy gap between the excited and ground states, resulting in reduced trans isomer production. Some directions for the extension of the model description are also discussed.

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Section: Friction Kernels Description and Parametrizationmentioning

confidence: 99%

Section: Inclusion Of Dissipative Effects For the Psb And The Solventmentioning

confidence: 99%

Dynamical Friction Effects on the Photoisomerization of a Model Protonated Schiff Base in Solution

2010

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“…Non-equilibrium molecular dynamics (NEMD) simulations [33][34][35][36][37][38] and the Landau-Teller (LT) approach combined with equilibrium molecular dynamics (EMD) simulations [39][40][41][42][43][44][45] are the most widely used theoretical methods for investigating VER of polyatomic molecules in solution. The former is the most straightforward and reliable method when classical mechanics is applicable.…”

Section: Introductionmentioning

confidence: 99%

Molecular dynamics modeling of cooling of vibrationally highly excited carbon dioxide produced in the photodissociation of organic peroxides in solution

Kandratsenka

Schroeder

Schwarzer

et al. 2005

Phys. Chem. Chem. Phys.

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Non-equilibrium (NEMD) and equilibrium (EMD) molecular dynamics simulations are performed to investigate the vibrational cooling and asymmetric stretch spectral evolution of highly excited carbon dioxide produced in the photodissociation of organic peroxides in the solvents dichloromethane, carbon tetrachloride and xenon. Due to strong Fermi resonance the symmetric stretching and bending modes of carbon dioxide in CH2Cl2 and CCl4 jointly relax on a ten and hundred picosecond timescale, respectively, which is in accordance with experiment. However, the high frequency CO2 asymmetric stretch vibration relaxes on a considerably longer time scale because of weak interaction with the other modes. The relaxation rate coefficients of (and works done by) different modes obtained from NEMD and the Landau-Teller rate coefficients calculated through equilibrium force time correlation functions are in reasonable agreement. The analysis of these results leads to the conclusion that, in contrast to xenon where the relaxation takes about 20 ns, the shorter time scales in CH2Cl2 and CCl4 are caused by efficient near resonant vibration to vibration energy transfer from carbon dioxide to solvent molecules. The results of the non-equilibrium simulations are used to monitor the quasi-stationary asymmetric stretch infrared spectra of carbon dioxide during the cooling process. Comparison of the corresponding experimental results suggests that carbon dioxide initially is produced with a broad distribution of energy disposed in its bend and symmetric stretch modes while the asymmetric stretch mode remains unexcited.

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“…Here, we simply display them in Figure 8, noting the following features. The kernels for r and θ have the same time dependence suitable for bound coordinates,45, 46, 50 with the initial amplitude of the latter being about four times larger than for the former (reflecting the larger effective size of the relevant PSB portion for rotation compared to translation). The solvent friction kernels are Gaussian functions in time, with a characteristic time about three times smaller for H 2 O than for CH 3 CN (reflecting the former's faster reorientation), and with an initial friction amplitude about two times larger for H 2 O than for CH 3 CN (reflecting the former's hydrogen bonding interactions).…”

Section: Dynamical Descriptionmentioning

confidence: 99%

Conical intersection structure and dynamics for a model protonated schiff base photoisomerization in solution

Malhado

Spezia

Hynes

2012

Int J of Quantum Chemistry

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Here, we present some highlights of our recent study [Malhado et al. J. Phys. Chem. A 115, 3729 (2011)] of the photoisomerization involving a conical intersection for a model protonated Schiff base (PSB) in modeled water and acetonitrile solvents, in which the inclusion of energy-and momentum-transfer effects is described via a generalized Langevin equation (GLE) frictional approach and surface-hopping dynamics. Short-time GLE frictional effects on the model's three coordinates, the intramolecular bond length alternation, and torsional PSB coordinates and a solvent coordinate, have a number of important features. Among these are the general feature of accelerating nonadiabatic transitions to the ground electronic state and a predicted preferential higher proportion of ground-state trans isomer, that is, a successful cis to trans photoreaction. This preference is solvent-dependent and is enhanced in water solvent with its higher friction intensity and short time scales.

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Energy and capacity time correlation functions for investigation of vibrational energy relaxation

Cited by 6 publications

References 54 publications

Dynamical Friction Effects on the Photoisomerization of a Model Protonated Schiff Base in Solution

Dynamical Friction Effects on the Photoisomerization of a Model Protonated Schiff Base in Solution

Molecular dynamics modeling of cooling of vibrationally highly excited carbon dioxide produced in the photodissociation of organic peroxides in solution

Conical intersection structure and dynamics for a model protonated schiff base photoisomerization in solution

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