Rovibrational quantum dynamical computations for deuterated isotopologues of the methane–water dimer

Sarka, János; Császár, Attila G.; Mátyus, Edit

doi:10.1039/c7cp02061a

Cited by 25 publications

(50 citation statements)

References 34 publications

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“…In the '3D( B 0 )' column, we report the bound vibrational energies obtained with an 'adjusted' 3D model. While using the r C-H 0 value for defining the 3D cut of the PES, we adjusted the C-H distance in the KEO to reproduce the B 0 effective rotational constant of this PES in 2D coupled-rotor computations [8,36]. This model reproduces the correct number of bound states and has a smaller, 0.32 cm −1 rms, than the 3D model with the rigorous geometrical constraints.…”

Section: Full-dimensional (12d) Vibrational States and Comparison mentioning

confidence: 99%

Exact quantum dynamics background of dispersion interactions: case study for CH₄·Ar in full (12) dimensions

Avila

Papp

Czakó

et al. 2020

Phys. Chem. Chem. Phys.

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A full-dimensional ab initio potential energy surface of spectroscopic quality is developed for the van-der-Waals complex of a methane molecule and an argon atom. Variational vibrational states are computed on this surface including all twelve (12) vibrational degrees of freedom of the methaneargon complex using the GENIUSH computer program and the Smolyak sparse grid method.The full-dimensional computations make it possible to study fine details of the interaction and distortion effects and to make a direct assessment of the reduced-dimensionality models often used in the quantum dynamics study of weakly bound complexes. A 12-dimensional (12D) vibrational computation including only a single harmonic oscillator basis function (9D) to describe the methane fragment (for which we use the ground-state effective structure as the reference structure) has a 0.40 cm −1 root-mean-square error (rms) with respect to the converged 12D bound-state excitation energies, which is less than half of the rms of the 3D model set up with the r 0 methane structure.Allowing 10 basis functions for the methane fragment, the rms of the bound state vibrational energies is reduced to 0.07 cm −1 , which is much better than the 3D models. The full-dimensional potential energy surface correctly describes the dissociation of the system, which together with further development of the variational (ro)vibrational methodology opens the route for the study of the role of dispersion forces on the excited methane vibrations and the energy transfer from the intra-to the intermolecular vibrational modes. * Gustavo Avila@telefonica.net †

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Section: Full-dimensional (12d) Vibrational States and Comparison mentioning

confidence: 99%

Exact quantum dynamics background of dispersion interactions: case study for CH₄·Ar in full (12) dimensions

Avila

Papp

Czakó

et al. 2020

Phys. Chem. Chem. Phys.

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“…We carried out rovibrational computation on this intermolecular PES using the GENIUSH program [11,12]. GENIUSH stands for GENeral Internal-coordinate, USer-define Hamiltonians, and it has been successfully used for the computation of bound and resonance states of floppy molecular systems, including ArNO + [13], HeH + 2 [14], NH 3 [11,12], H + 5 [15], CH + 5 [16], CH 4 ·H 2 O [4,5], with various internal coordinate and frame definitions. An interesting feature, the existence of formally negative-energy rotational excitations [4,5,15,[17][18][19] had been observed in a growing number of floppy systems and led to the introduction of the notion astructural molecules in Ref.…”

Section: B Rovibrational Computationsmentioning

confidence: 99%

“…A difference in the mathematical structure of the GM and SM splittings is that the totally symmetric vibrations (such as the zero-point vibration) of the SM contain a doubly-degenerate species. proach of GENIUSH and is called the coupled-rotor decomposition (CRD) [5].…”

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Bound and unbound rovibrational states of the methane-argon dimer

Ferenc

Mátyus

2018

Molecular Physics

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Peculiarities of the intermolecular rovibrational quantum dynamics of the methane-argon complex are studied using a new, ab initio potential energy surface [Y. N. Kalugina, S. E. Lokshtanov, V. N. Cherepanov, and A. A. Vigasin, J. Chem. Phys. 144, 054304 (2016)], variational rovibrational computations, and detailed symmetry considerations within the molecular symmetry group of this floppy complex as well as within the point groups corresponding to the local minimum structures. The computed (ro)vibrational states up to and beyond the dissociation asymptote are characterized using two limiting models: the rigidly rotating molecule's model and the coupled-rotor model of the rigidly rotating methane and an argon atom orbiting around it. * matyus@chem.elte.hu 1

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“…In FBR and DVR calculations, it is common to use a direct product basis. 11,[16][17][18][19][20][21][22][23][24][25] .…”

Section: Introductionmentioning

confidence: 99%

Using collocation and a hierarchical basis to solve the vibrational Schrödinger equation

Żak

Carrington

2019

The Journal of Chemical Physics

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We show that it is possible to compute vibrational energy levels of polyatomic molecules with a collocation method and a basis of products of one-dimensional harmonic oscillator functions pruned so that it does not include functions for which the indices of many of the one-dimensional functions are non-zero. Functions with many non-zero indices are coupled only by terms that depend simultaneously on many coordinates and they are typically small. The collocation equation is derived without invoking differences of interpolation operators, which simplifies implementation of the method. This, however, requires inverting a matrix whose elements are values of the pruned basis functions at the collocation points. The collocation points are the points on a Smolyak grid whose size is equal to the size of the pruned basis set.The Smolyak grid is built from symmetrized Leja points. Because both the basis and the grid are not tensor products, the inverse is not straightforward. It can be done by using so-called hierarchical 1-D basis functions. They are defined so that the matrix whose elements are the 1-D hierarchical basis functions evaluated at points is lower triangular. We test the method by applying it to compute 100 energy levels of CH 2 NH with an iterative eigensolver. a)

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Rovibrational quantum dynamical computations for deuterated isotopologues of the methane–water dimer

Cited by 25 publications

References 34 publications

Exact quantum dynamics background of dispersion interactions: case study for CH₄·Ar in full (12) dimensions

Exact quantum dynamics background of dispersion interactions: case study for CH₄·Ar in full (12) dimensions

Bound and unbound rovibrational states of the methane-argon dimer

Using collocation and a hierarchical basis to solve the vibrational Schrödinger equation

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Rovibrational quantum dynamical computations for deuterated isotopologues of the methane–water dimer

Cited by 25 publications

References 34 publications

Exact quantum dynamics background of dispersion interactions: case study for CH4·Ar in full (12) dimensions

Exact quantum dynamics background of dispersion interactions: case study for CH4·Ar in full (12) dimensions

Bound and unbound rovibrational states of the methane-argon dimer

Using collocation and a hierarchical basis to solve the vibrational Schrödinger equation

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Exact quantum dynamics background of dispersion interactions: case study for CH₄·Ar in full (12) dimensions

Exact quantum dynamics background of dispersion interactions: case study for CH₄·Ar in full (12) dimensions