Theoretical studies of the tunneling splitting of malonaldehyde using the multiconfiguration time-dependent Hartree approach

Schröder, Markus; Gatti, Fabien; Meyer, Hans‐Dieter

doi:10.1063/1.3600343

Cited by 112 publications

(100 citation statements)

References 51 publications

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“…Additional convergence calculations are performed based on extrapolation schemes proposed recently. 48,49 The idea is to carry out a reference calculation by employing a small set of SPFs, and in turn by doubling the number of SPFs in each mode independently to calculate the energy difference with respect to the reference one. At the end the sum of all these differences is added to the reference energy to estimate its extrapolated value.…”

Section: Zero-point Energy and Ground-state Propertiesmentioning

confidence: 99%

Vibrational dynamics of the ${\rm H}_5^+$H5+ and its isotopologues from multiconfiguration time-dependent Hartree calculations

Valdés

Prosmiti

Delgado‐Barrio

2012

The Journal of Chemical Physics

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(2010)]. The potential energy operators are constructed using the n-mode representation adapted to a four-combined mode cluster expansion, including up to seven-dimensional grids, chosen adequately to take advantage in representing the MCTDH wavefunction. An error analysis is performed to quantify the convergence of the potential expansion to reproduce the reference surfaces at the energies of interest. An extensive analysis of the vibrational ground state properties of these isotopes and comparison with the reference diffusion Monte Carlo results by Acioli et al. [J. Chem. Phys. 128, 104318 (2008)] are presented. It is found that these systems are highly delocalized, interconverting between equivalent minima through rotation and internal proton transfer motions even at their vibrational ground state. Isotopic substitution affects the zero-point energy and structure, showing preference in the arrangements of the H and D within the mixed clusters, and the most stable conformers of each isotopomer are the ones with the H in the central position. Vibrational excited states are also computed and by comparing the energies and structures predicted from the two surfaces, the effect of the potential topology on them is discussed.

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Section: Zero-point Energy and Ground-state Propertiesmentioning

confidence: 99%

Vibrational dynamics of the ${\rm H}_5^+$H5+ and its isotopologues from multiconfiguration time-dependent Hartree calculations

Valdés

Prosmiti

Delgado‐Barrio

2012

The Journal of Chemical Physics

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“…[4], we derived the conditions that vibrational conical intersections occur and presented quantum-dynamical model calculations to show the consequences for the vibrational dynamics and spectra. As a first simple example, we considered malonaldehyde which is a prototype molecule with a medium strong intramolecular hydrogen bond [10,[12][13][14][15][16]. We showed that a conical intersection exists between the first excited states of the OH stretch and the OH bend modes, respectively, which might provide an explanation for the ultrafast (a few 100 fs) vibrational relaxation and the complex oscillatory features found in infrared time-resolved pump-probe experiments for this type of molecular systems [17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Vibrational conical intersections in the water dimer

Hamm

Stock

2013

Molecular Physics

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A recent paper (Phys. Rev. Lett. 109, 173201, 2012) has introduced the concept of vibrational conical intersections as a potential source of ultrafast vibrational relaxation, using the coupling between high-frequency OH modes and low-frequency intramolecular hydrogen bonding modes of malonaldehyde as an example. Here, the question is addressed whether such conical intersections may also appear for intermolecular hydrogen bonds. To that end, the water dimer is studied as a minimal model for the hydrogen bonding in liquid water. Although a significant separation of time scales between intra-and intermolecular degrees of freedom exists in (H2O)2, a standard normal mode description is found to lead to a complete break-down of the adiabatic ansatz. This is due to strong nonlinear couplings between high-and low-frequency normal modes, which in turn give rise to large overall nonadiabatic couplings. A valid adiabatic picture is obtained, on the other hand, when internal coordinates are employed. The resulting adiabatic potential energy surfaces indeed exhibit low-lying conical intersections, whose possible relevance for ultrafast relaxation and energy transfer in water is discussed. AbstractA recent paper (Phys. Rev. Lett. 109, 173201, 2012) has introduced the concept of vibrational conical intersections as a potential source of ultrafast vibrational relaxation, using the coupling between high-frequency OH modes and low-frequency intramolecular hydrogen bonding modes of malonaldehyde as an example. Here, the question is addressed whether such conical intersections may also appear for intermolecular hydrogen bonds. To that end, the water dimer is studied as a minimal model for the hydrogen bonding in liquid water. Although a significant separation of time scales between intra-and intermolecular degrees of freedom exists in (H 2 O) 2 , a standard normal mode description is found to lead to a complete break-down of the adiabatic ansatz. This is due to strong nonlinear couplings between high-and low-frequency normal modes, which in turn give rise to large overall nonadiabatic couplings. A valid adiabatic picture is obtained, on the other hand, when internal coordinates are employed. The resulting adiabatic potential energy surfaces indeed exhibit low-lying conical intersections, whose possible relevance for ultrafast relaxation and energy transfer in water is discussed.

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“…4a). Its tunnel-splitting and intramolecular hydrogen-bond transfer has been studied extensively [14,[29][30][31][32], while we concentrate here on the dynamics within one of the potential energy wells. We treated the molecule on the MP2/6-311++g(2df,2pd) quantum-chemical level of theory, using the Gaussian program package [33].…”

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confidence: 99%

Vibrational Conical Intersections as a Mechanism of Ultrafast Vibrational Relaxation

Hamm

Stock

2012

Phys. Rev. Lett.

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Presenting true crossings of adiabatic potential energy surfaces, conical intersections are a paradigm of ultrafast and efficient electronic relaxation dynamics. The same mechanism is shown to apply also for vibrational conical intersections, which may occur when two high-frequency modes (such as OH stretch vibrations) are coupled to low-frequency modes (such as hydrogen bonding modes). By derivation of a model Hamiltonian and its parametrization for a concrete example, malonaldehyde, the conditions that such conical intersections occur are identified and the consequences for the vibrational dynamics and spectra are demonstrated.

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Theoretical studies of the tunneling splitting of malonaldehyde using the multiconfiguration time-dependent Hartree approach

Cited by 112 publications

References 51 publications

Vibrational dynamics of the ${\rm H}_5^+$H5+ and its isotopologues from multiconfiguration time-dependent Hartree calculations

Vibrational dynamics of the ${\rm H}_5^+$H5+ and its isotopologues from multiconfiguration time-dependent Hartree calculations

Vibrational conical intersections in the water dimer

Vibrational Conical Intersections as a Mechanism of Ultrafast Vibrational Relaxation

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