Hierarchical expansion of the kinetic energy operator in curvilinear coordinates for the vibrational self-consistent field method

Strobusch, Daniel; Scheurer, Ch.

doi:10.1063/1.3637629

Cited by 32 publications

(32 citation statements)

References 41 publications

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“…This success is entirely dependent on the use of the reaction path coordinate system. Other choices of coordinates would fare worse with this mean-field-based approach [19]. [35][36][37][38].…”

Section: Comparing Variational and Vmp2 Predictionsmentioning

confidence: 99%

“…The semi-experimental structure requires theoretical input from rovibrational calculations, for which we turn to numerically exact variational methods. These results also serve as a useful reference for assessing the performance of approximate rovibrational methods, in particular curvilinear coordinate vibrational second order Møller-Plesset perturbation theory (VMP2) [17][18][19] and a recently developed extension for J > 0 rovibrational calculations [20]. The use of a curvilinear coordinate description makes this method applicable to molecules exhibiting large amplitude nuclear motion.…”

Section: Introductionmentioning

confidence: 99%

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The equilibrium structure of hydrogen peroxide

Baraban

Changala

Stanton

2018

Journal of Molecular Spectroscopy

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The equilibrium structure of hydrogen peroxide is completely determined for the first time. Recent isotopically substituted data is combined with the results of rovibrational variational calculations to yield a complete semi-experimental structure, which is in excellent agreement with high level ab initio calculated structures. In addition to numerically exact variational calculations, we also investigate the accuracy of approximate rovibrational predictions based on second order vibrational Møller-Plesset perturbation theory with curvilinear coordinates.

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Section: Comparing Variational and Vmp2 Predictionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The equilibrium structure of hydrogen peroxide

Baraban

Changala

Stanton

2018

Journal of Molecular Spectroscopy

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“…A lot of progress has been made developing methods for solving the nuclear vibrational Schrödinger equation, which have been described in some recent reviews . However, harmonic normal mode analysis remains the most widely used method for solving the nuclear vibrational Schrödinger equation.…”

Section: Introductionmentioning

confidence: 99%

The PyPES library of high quality semi‐global potential energy surfaces

Sibaev

Crittenden

2015

J Comput Chem

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In this article, we present a Python-based library of high quality semi-global potential energy surfaces for 50 polyatomic molecules with up to six atoms. We anticipate that these surfaces will find widespread application in the testing of new potential energy surface construction algorithms and nuclear ro-vibrational structure theories. To this end, we provide the ability to generate the energy derivatives required for Taylor series expansions to sixth order about any point on the potential energy surface in a range of common coordinate systems, including curvilinear internal, Cartesian, and normal mode coordinates. The PyPES package, along with FORTRAN, C, MATLAB and Mathematica wrappers, is available at http://sourceforge.net/projects/pypes-lib.

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“…It has been shown that the local coordinates provide a Hamiltonian that is less coupled and beneficial in describing, for example, stretching vibrations of X-H (X=C, N, O) bonds, [27][28][29][30] the wagging of −NH 2 group, 31 the torsion of −OH group, [32][33][34][35] −CH 3 group, 36 etc. Although the curved motion of the internal coordinates gives rise to complex kinematic coupling in the kinetic energy operator, the techniques to automatically compute the kinetic energy terms have recently evolved.…”

Section: Introductionmentioning

confidence: 99%

Optimized coordinates in vibrational coupled cluster calculations

Thomsen

Yagi

Christiansen

2014

The Journal of Chemical Physics

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Articles you may be interested inOrbitally invariant internally contracted multireference unitary coupled cluster theory and its perturbative approximation: Theory and test calculations of second order approximation J. Chem. Phys. 137, 014108 (2012); 10.1063/1.4731634 Accurate calculation of vibrational frequencies using explicitly correlated coupled-cluster theory Accurate calculation of anharmonic vibrational frequencies of medium sized molecules using local coupled cluster methods J. Chem. Phys. 126, 134108 (2007); 10.1063/1.2718951 MRCI calculations on the helium dimer employing an interaction optimized basis setThe use of variationally optimized coordinates, which minimize the vibrational self-consistent field (VSCF) ground state energy with respect to orthogonal transformations of the coordinates, has recently been shown to improve the convergence of vibrational configuration interaction (VCI) towards the exact full VCI [K. Yagi, M. Keçeli, and S. Hirata, J. Chem. Phys. 137, 204118 (2012)]. The present paper proposes an incorporation of optimized coordinates into the vibrational coupled cluster (VCC), which has in the past been shown to outperform VCI in approximate calculations where similar restricted state spaces are employed in VCI and VCC. An embarrassingly parallel algorithm for variational optimization of coordinates for VSCF is implemented and the resulting coordinates and potentials are introduced into a VCC program. The performance of VCC in optimized coordinates (denoted oc-VCC) is examined through pilot applications to water, formaldehyde, and a series of water clusters (dimer, trimer, and hexamer) by comparing the calculated vibrational energy levels with those of the conventional VCC in normal coordinates and VCI in optimized coordinates. For water clusters, in particular, oc-VCC is found to gain orders of magnitude improvement in the accuracy, exemplifying that the combination of optimized coordinates localized to each monomer with the size-extensive VCC wave function provides a supreme description of systems consisting of weakly interacting sub-systems.

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Hierarchical expansion of the kinetic energy operator in curvilinear coordinates for the vibrational self-consistent field method

Cited by 32 publications

References 41 publications

The equilibrium structure of hydrogen peroxide

The equilibrium structure of hydrogen peroxide

The PyPES library of high quality semi‐global potential energy surfaces

Optimized coordinates in vibrational coupled cluster calculations

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