Infrared and Raman Spectroscopy of Liquid Water through “First-Principles” Many-Body Molecular Dynamics

Medders, Gregory R.; Paesani, Francesco

doi:10.1021/ct501131j

Cited by 233 publications

(371 citation statements)

References 111 publications

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“…22,56,57 Moreover, ab initio based FF models have been applied for simulating interfacial water. 24,25,[58][59][60][61][62] The third category is that of coarse-grained (CG) MD techniques. Although different routes for CGMD simulation have been presented, the concept underlying CG approaches is common: beads representing a collection of atoms are used to reduce the number of particles in the simulation and enlarge the time step.…”

Section: Molecular Dynamics Simulation At Aqueous Interfacesmentioning

confidence: 99%

Molecular Modeling of Water Interfaces: From Molecular Spectroscopy to Thermodynamics

et al. 2016

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Understanding aqueous interfaces at the molecular level is not only fundamentally important, but also highly relevant for a variety of disciplines. For instance, electrode-water interfaces are relevant for electrochemistry, as are mineral-water interfaces for geochemistry and air-water interfaces for environmental chemistry; water-lipid interfaces constitute the boundaries of the cell membrane, and are thus relevant for biochemistry. One of the major challenges in these fields is to link macroscopic properties such as interfacial reactivity, solubility, and permeability as well as macroscopic thermodynamic and spectroscopic observables to the structure, structural changes, and dynamics of molecules at these interfaces. Simulations, by themselves, or in conjunction with appropriate experiments, can provide such molecular-level insights into aqueous interfaces. In this contribution, we review the current state-of-the-art of three levels of molecular dynamics (MD) simulation: ab initio, force field, and coarse-grained. We discuss the advantages, the potential, and the limitations of each approach for studying aqueous interfaces, by assessing computations of the sum-frequency generation spectra and surface tension. The comparison of experimental and simulation data provides information on the challenges of future MD simulations, such as improving the force field models and the van der Waals corrections in ab initio MD simulations. Once good agreement between experimental observables and simulation can be established, the simulation can be used to provide insights into the processes at a level of detail that is generally inaccessible to experiments. As an example we discuss the mechanism of the evaporation of water. We finish by presenting an outlook outlining four future challenges for molecular dynamics simulations of aqueous interfacial systems.

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Section: Molecular Dynamics Simulation At Aqueous Interfacesmentioning

confidence: 99%

Molecular Modeling of Water Interfaces: From Molecular Spectroscopy to Thermodynamics

et al. 2016

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“…[29][30][31][32] Although both methods have known artifacts, such as the spurious-mode effect in RPMD [33][34][35] and the curvature problem 35,36 in CMD, they have proven effective for a vast range of chemical applications including the calculation of thermal rate constants, 30,[37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55] diffusion coefficients, 31,[56][57][58][59][60][61] and vibrational spectra. [33][34][35][36][62][63][64][65] With only a few exceptions, [66][67][68] RPMD and CMD have been applied for the characterization of processes with thermal equilibrium initial conditions. The aim of this work is to systematically investigate whether RPMD and CMD can also be ...…”

Section: Introductionmentioning

confidence: 99%

Non-equilibrium dynamics from RPMD and CMD

Welsch

Song

Shi

et al. 2016

The Journal of Chemical Physics

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We investigate the calculation of approximate non-equilibrium quantum time correlation functions (TCFs) using two popular path-integral-based molecular dynamics methods, ring-polymer molecular dynamics (RPMD) and centroid molecular dynamics (CMD). It is shown that for the cases of a sudden vertical excitation and an initial momentum impulse, both RPMD and CMD yield non-equilibrium TCFs for linear operators that are exact for high temperatures, in the t = 0 limit, and for harmonic potentials; the subset of these conditions that are preserved for non-equilibrium TCFs of non-linear operators is also discussed. Furthermore, it is shown that for these non-equilibrium initial conditions, both methods retain the connection to Matsubara dynamics that has previously been established for equilibrium initial conditions. Comparison of non-equilibrium TCFs from RPMD and CMD to Matsubara dynamics at short times reveals the orders in time to which the methods agree. Specifically, for the position-autocorrelation function associated with sudden vertical excitation, RPMD and CMD agree with Matsubara dynamics up to O(t4) and O(t1), respectively; for the position-autocorrelation function associated with an initial momentum impulse, RPMD and CMD agree with Matsubara dynamics up to O(t5) and O(t2), respectively. Numerical tests using model potentials for a wide range of non-equilibrium initial conditions show that RPMD and CMD yield non-equilibrium TCFs with an accuracy that is comparable to that for equilibrium TCFs. RPMD is also used to investigate excited-state proton transfer in a system-bath model, and it is compared to numerically exact calculations performed using a recently developed version of the Liouville space hierarchical equation of motion approach; again, similar accuracy is observed for non-equilibrium and equilibrium initial conditions.

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“…13,14 To address this issue, we recently introduced a unified methodology for modeling molecular systems, denoted manybody molecular dynamics (MB-MD), which is built entirely upon correlated electronic structure data and includes a quantum-mechanical description of the molecular motion. 15 By construction, MB-MD thus enables "first principles" calculations of structural, thermodynamic, dynamical, and spectroscopic properties of molecular systems from the gas to the condensed phase. Limiting our focus to vibrational spectroscopy, the infrared (IR) spectrum of a generic molecular system can be obtained, 16,17 within the electric dipole approximation and linear response theory, from the Fourier transform of the quantum time autocorrelation function of the system's dipole moment,…”

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confidence: 99%

“…15 While dynamical effects, such as motional narrowing, play an important role in determining the final line shapes, 18-20 from a static perspective, the IR spectrum can be related to the frequencies of the vibrational modes determined by the multidimensional potential energy surface weighted by the associated squared transition dipoles. In this contribution, we seek to understand the roles of both PES and DMS in determining the IR activity of liquid water by investigating the properties of three different molecular models that have been previously applied to the study of IR spectra.…”

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On the interplay of the potential energy and dipole moment surfaces in controlling the infrared activity of liquid water

Medders

Paesani

2015

The Journal of Chemical Physics

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Infrared vibrational spectroscopy is a valuable tool for probing molecular structure and dynamics. However, obtaining an unambiguous molecular-level interpretation of the spectral features is made difficult, in part, due to the complex interplay of the dipole moment with the underlying vibrational structure. Here, we disentangle the contributions of the potential energy surface (PES) and dipole moment surface (DMS) to the infrared spectrum of liquid water by examining three classes of models, ranging in complexity from simple point charge models to accurate representations of the many-body interactions. By decoupling the PES from the DMS in the calculation of the infrared spectra, we demonstrate that the PES, by directly modulating the vibrational structure, primarily controls the width and position of the spectroscopic features. Due to the dependence of the molecular dipole moment on the hydration environment, many-body electrostatic effects result in a ∼100 cm(-1) redshift in the peak of the OH stretch band. Interestingly, while an accurate description of many-body collective motion is required to generate the correct (vibrational) structure of the liquid, the infrared intensity in the OH stretching region appears to be a measure of the local structure due to the dominance of the one-body and short-ranged two-body contributions to the total dipole moment.

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Infrared and Raman Spectroscopy of Liquid Water through “First-Principles” Many-Body Molecular Dynamics

Cited by 233 publications

References 111 publications

Molecular Modeling of Water Interfaces: From Molecular Spectroscopy to Thermodynamics

Molecular Modeling of Water Interfaces: From Molecular Spectroscopy to Thermodynamics

Non-equilibrium dynamics from RPMD and CMD

On the interplay of the potential energy and dipole moment surfaces in controlling the infrared activity of liquid water

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