Quantum and classical study of vibrational states of H and H molecules

Gargano

et al. 2008

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ABSTRACT:In this article we present a characterization of the vibrational spectrum of the H 5 ϩ molecule using the correlation function quantum Monte Carlo (CFQMC) method and a genetic algorithm study of the topology of the potential energy surface (PES) used. The vibrational modes associated with the H 3 ϩ -H 2 torsion and stretching possess very flat minima. As a consequence the fundamental frequencies corresponding to these modes are poorly described in the harmonic approximation. In our genetic algorithm study of the PES using Cartesian coordinates we have found some unexpected minima. A careful analysis shows that, in the curvilinear coordinates in which the potential is described, some of these minima have identical coordinates. Nevertheless, they represent nonequivalent molecular geometries. The vibrational frequencies obtained in this work are not in good agreement with available experimental data as well as other computational methods. It shows that our method of detailed analysis of PESs could reveal shortcomings introduced by the use of curvilinear coordinates.

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quantum Monte Carlo and genetic algorithm study of the potential energy surface of the H molecule

Gargano

et al. 2008

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“…The H þ 2 study is of great interest to theoretical chemists, spectroscopics and astrophysicists [13][14][15]. Furthermore, there is much interest in the H þ 2 spectroscopic properties for astronomical informations [16,17].…”

Section: Introductionmentioning

confidence: 99%

H₂⁺ dynamical properties in the electronic states 7jσ, 8jσ, 8kσ, 7iπ, and 8jp

Kiametis

Matheus

Fonseca

et al. 2011

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We have theoretically calculated the H þ 2 dynamical properties in the electronic states 7jr, 8jr, 8kr, 7ip, and 8jp. More precisely, we have evaluated the H þ 2 rovibrational energies, x e , x e x e , x e y e , and c e using electronic energies obtained from the solution of Hamilton-Jacobi equation in association with the series established by Wind-Jaffe. The x e calculated values are in a good accordance with theoretical data available in the literature. Furthermore, the H þ 2 rovibrational energies, x e x e , x e y e , and c e values are shown here for the first time in the literature.

“…In addition, the thorough investigation of these systems is invaluable to theoretical chemists, spectroscopics, and astrophysicists [10][11][12]. More specifically, there is, for astronomic purposes [13,14], a great deal of importance particularly concerning the spectroscopic properties of the H + 2 ion, as it is believed to be a major component in stellar atmospheres as well as in upper atmospheres of rich-in-hydrogen planets such as Jupiter [15].…”

Section: Introductionmentioning

confidence: 99%

Calculation of the H₂⁺ rovibrational energies and spectroscopic constants in the 2pπ, 3dσ, 4dσ, 4fπ, 4fσ, 5gσ, and 6iσ electronic states

Vila

Leal

Fonseca

et al. 2011

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Starting with the Hamilton‐Jacobi equation, Campos et al. have applied Hylleraas' method along with the series obtained by Wind‐Jaffe to several molecular ions, among which the H2+ system, to determine their electronic energies in different states. In this work, we have fitted the potential energy curves for the 2pπ, 3dσ, 4dσ, 4fπ, 4fσ, 5gσ, and 6iσ electronic states of the H2+ ion employing the Rydberg generalized function. From these fittings, the spectroscopic constants and the rovibrational energies have been determined by two distinct methods: Dunham's and the discrete variable representation. The theoretically obtained results are in a satisfactory agreement and are expected to provide a comparison source to future works in the experimental field. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011