Bulk and surface energetics of crystalline lithium hydride: Benchmarks from quantum Monte Carlo and quantum chemistry

S. J. Binnie, S. J. Nolan, N. D. Drummond, D. Alfe, N. L. Allan, F. R. Manby, M. J. Gillan

Research output: Contribution to journalArticle (Academic Journal)peer-review

26 Citations (Scopus)


We show how accurate benchmark values of the surface formation energy of crystalline lithium hydride can be computed by the complementary techniques of quantum Monte Carlo (QMC) and wave-function-based molecular quantum chemistry. To demonstrate the high accuracy of the QMC techniques, we present a detailed study of the energetics of the bulk LiH crystal, using both pseudopotential and all-electron approaches. We show that the equilibrium lattice parameter agrees with experiment to within 0.03%, which is around the experimental uncertainty, and the cohesive energy agrees to within around 10 meV/f.u. QMC in periodic slab geometry is used to compute the formation energy of the LiH (001) surface, and we show that the value can be accurately converged with respect to slab thickness and other technical parameters. The quantum chemistry calculations build on the recently developed hierarchical scheme for computing the correlation energy of a crystal to high precision. We show that the hierarchical scheme allows the accurate calculation of the surface formation energy, and we present results that are well converged with respect to basis set and with respect to the level of correlation treatment. The QMC and hierarchical results for the surface formation energy agree to within about 1%.

Original languageEnglish
Article number165431
Pages (from-to)-
Number of pages10
JournalPhysical Review B: Condensed Matter and Materials Physics
Issue number16
Publication statusPublished - 19 Oct 2010

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