Vibrational relaxation of I−2 in water and ethanol: molecular dynamics simulation

Benjamin, Ilan; Whitnell, Robert M.

doi:10.1016/0009-2614(93)85603-l

Cited by 112 publications

(105 citation statements)

References 23 publications

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“…A very popular scheme is to obtain the memory kernel from the time-correlation function (TCF) of the forces exerted on a frozen system coordinate, referred to as the rigid bond approach [8,9,11,42]. However, Berne et al [43] have shown that this ansatz is only correct when the system frequency is much larger than the bath ones.…”

Section: Introductionmentioning

confidence: 99%

“…Situations where memory effects become important are accounted for by the generalized Langevin equation (GLE) [5][6][7] via a frequencydependent friction and a stochastic force with a finite correlation time. This generalized equation has been employed for instance, in the theory of vibrational relaxation for estimating characteristic relaxation times [8][9][10][11], reaction rates [12] and for thermostatting purposes [13][14][15]; see e.g. Refs.…”

Section: Introductionmentioning

confidence: 99%

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Parametrizing linear generalized Langevin dynamics from explicit molecular dynamics simulations

Gottwald

Karsten

Ivanov

et al. 2015

The Journal of Chemical Physics

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Fundamental understanding of complex dynamics in many-particle systems on the atomistic level is of utmost importance. Often the systems of interest are of macroscopic size but can be partitioned into few important degrees of freedom which are treated most accurately and others which constitute a thermal bath. Particular attention in this respect attracts the linear generalized Langevin equation (GLE), which can be rigorously derived by means of a linear projection (LP) technique. Within this framework a complicated interaction with the bath can be reduced to a single memory kernel. This memory kernel in turn is parametrized for a particular system studied, usually by means of time-domain methods based on explicit molecular dynamics data. Here we discuss that this task is most naturally achieved in frequency domain and develop a Fourier-based parametrization method that outperforms its time-domain analogues. Very surprisingly, the widely used rigid bond method turns out to be inappropriate in general. Importantly, we show that the rigid bond approach leads to a systematic underestimation of relaxation times, unless the system under study consists of a harmonic bath bi-linearly coupled to the relevant degrees of freedom. INTRODUCTIONStudying complex dynamics of many-particle systems has become one of the main goals in modern molecular physics. The fundamental understanding of the underlying microscopical processes requires the interplay of elaborate experimental techniques and sophisticated theoretical approaches. Experimentally, (non-)linear spectroscopy revealed itself as a powerful tool for probing the dynamics and for determining the characteristic timescales, such as dephasing/relaxation times and reaction rates to name but two. For interpreting the experimental spectra theoretical models are needed which can give insight into the atomistic dynamics. Often, a reduction of the description to few variables is convenient in many cases since this can not only ease the interpretation, but enable the identification of key properties [1]. Such a reduced description can formally be obtained from the so-called system-bath partitioning, where only a small subset of degrees of freedom (DOFs), referred to as system, is considered as important for describing a physical process under study. All the other DOFs, referred to as bath, are regarded as irrelevant in the sense that they might influence the time evolution of the system but do not explicitly enter any dynamical variable of interest. Practically, such a separation is often natural, for instance, when studying a reaction with a clearly defined reaction center or solute dynamics in a solvent environment. Further, reduced equations of motion (EOMs) for the system DOFs can be derived in which the influence of the bath is limited to dissipation and fluctuations.The most simple formulation of this idea is provided by the Markovian Langevin equation, where dissipation and fluctuations take the form of static friction and stochastic white noise, respectively [2][3][4]. Sit...

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Parametrizing linear generalized Langevin dynamics from explicit molecular dynamics simulations

Gottwald

Karsten

Ivanov

et al. 2015

The Journal of Chemical Physics

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“…Vibrational energy relaxation has been investigated based upon this kind of classical MD calculation for molecules composed of heavy atoms such as I2 [52] and I; ion [53] and for high-frequency N2 at very high temperature [54]. For example, the frequency of an I; ion is about 115 cm-'.…”

Section: A Classical Molecular Dynamicsmentioning

confidence: 99%

Dynamical Approach to Vibrational Relaxation

Okazaki

2001

Advances in Chemical Physics

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“…(12) analytically due to the known Fourier transforms of the fit functions, see Eq. (17). To test the applicability of such an alternative fitting procedure we compare the corresponding memory kernels against the ones obtained from the Gaussian filtering technique in Fig.…”

Section: Error Analysismentioning

confidence: 99%

“…Independently on the derivation, the general advantage of the GLE is that the dissipation and the statistical properties of the noise are entirely described by the so-called memory kernel being simply a function of time or, equivalently, by the spectral density as its frequency domain counterpart. Due to this simplicity, the GLE has been applied in many fields as, for instance, in the theory of vibrational relaxation for estimating characteristic relaxation times [16][17][18][19], reaction rates [20] and for thermostatting purposes [21][22][23]; see, e.g., Refs. [24][25][26] for review.…”

Section: Introductionmentioning

confidence: 99%

Vibrational spectroscopy via the Caldeira-Leggett model with anharmonic system potentials

Gottwald

Ivanov

Kühn

2016

The Journal of Chemical Physics

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Abstract. The Caldeira-Leggett (CL) model, which describes a system bi-linearly coupled to a harmonic bath, has enjoyed popularity in condensed phase spectroscopy owing to its utmost simplicity. However, the applicability of the model to cases with anharmonic system potentials, as it is required for the description of realistic systems in solution, is questionable due to the presence of the invertibility problem [J. Phys. Chem. Lett., 6, 2722Lett., 6, (2015] unless the system itself resembles the CL model form. This might well be the case at surfaces or in the solid regime, which we here confirm for a particular example of an iodine molecule in the atomic argon environment under high pressure. For this purpose we extend the recently proposed Fourier method for parameterizing linear generalized Langevin dynamics [J. Chem. Phys., 142, 244110 (2015)] to the non-linear case based on the CL model and perform an extensive error analysis. In order to judge on the applicability of this model in advance, we give handy empirical criteria and discuss the effect of the potential renormalization term. The obtained results provide evidence that the CL model can be used for describing a potentially broad class of systems.

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Vibrational relaxation of I−2 in water and ethanol: molecular dynamics simulation

Cited by 112 publications

References 23 publications

Parametrizing linear generalized Langevin dynamics from explicit molecular dynamics simulations

Parametrizing linear generalized Langevin dynamics from explicit molecular dynamics simulations

Dynamical Approach to Vibrational Relaxation

Vibrational spectroscopy via the Caldeira-Leggett model with anharmonic system potentials

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