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arXiv · 1108.2049

Assessing weak hydrogen binding on Ca+ centers: An accurate many-body study with large basis sets

Wirawan Purwanto·Henry Krakauer·Yudistira Virgus·Shiwei Zhang
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Abstract

Weak H2 physisorption energies present a significant challenge to even the best correlated theoretical many-body methods. We use the phaseless auxiliary-field quantum Monte Carlo (AFQMC) method to accurately predict the binding energy of Ca+ - 4H2. Attention has recently focused on this model chemistry to test the reliability of electronic structure methods for H2 binding on dispersed alkaline earth metal centers. A modified Cholesky decomposition is implemented to realize the Hubbard-Stratonovich transformation efficiently with large Gaussian basis sets. We employ the largest correlation-consistent Gaussian type basis sets available, up to cc-pCV5Z for Ca, to accurately extrapolate to the complete basis limit. The calculated potential energy curve exhibits binding with a double-well structure.

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Wirawan Purwanto, Henry Krakauer, Yudistira Virgus, Shiwei Zhang. 2011-11-01. Assessing weak hydrogen binding on Ca+ centers: An accurate many-body study with large basis sets. https://doi.org/10.1063/1.3654002

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