Hydrogen molecule in the small dodecahedral cage of a clathrate hydrate: Quantum five-dimensional calculations of the coupled translation-rotation eigenstates

Xu Minzhong, Yael S. Elmatad, Francesco Sebastianelli, Jules W. Moskowitz, Zlatko Bacic

Research output: Contribution to journalArticle

Abstract

We report quantum five-dimensional (5D) calculations of the energy levels and wave functions of the hydrogen molecule, para-H2 and ortho-H 2, confined inside the small dodecahedral (H2O)2o cage of the sII clathrate hydrate. All three translational and the two rotational degrees of freedom of H2 are included explicitly, as fully coupled, while the cage is treated as rigid. The 5D potential energy surface (PES) of the H2-cage system is pairwise additive, based on the high-quality ab initio 5D (rigid monomer) PES for the H2-H2O complex. The bound state calculations involve no dynamical approximations and provide an accurate picture of the quantum 5D translation-rotation dynamics of H 2 inside the cage. The energy levels are assigned with translational (Cartesian) and rotational quantum numbers, based on calculated root-mean-square displacements and probability density plots. The translational modes exhibit negative anharmonicity. It is found that j is a good rotational quantum number, while the threefold degeneracy of the j = 1 level is lifted completely. There is considerable translation-rotation coupling, particularly for excited translational states.

Original languageEnglish (US)
Pages (from-to)24806-24811
Number of pages6
JournalJournal of Physical Chemistry B
Volume110
Issue number49
DOIs
StatePublished - Dec 14 2006

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Potential energy surfaces
clathrates
Hydrates
hydrates
Electron energy levels
quantum numbers
Hydrogen
eigenvectors
energy levels
potential energy
Molecules
hydrogen
Wave functions
Excited states
molecules
monomers
degrees of freedom
Monomers
plots
wave functions

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Cite this

Hydrogen molecule in the small dodecahedral cage of a clathrate hydrate : Quantum five-dimensional calculations of the coupled translation-rotation eigenstates. / Minzhong, Xu; Elmatad, Yael S.; Sebastianelli, Francesco; Moskowitz, Jules W.; Bacic, Zlatko.

In: Journal of Physical Chemistry B, Vol. 110, No. 49, 14.12.2006, p. 24806-24811.

Research output: Contribution to journalArticle

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