 
Summary: Calculation of properties of crystalline lithium hydride using correlated wave function theory
S. J. Nolan,1 M. J. Gillan,2,3 D. Alfè,2,3,4 N. L. Allan,1 and F. R. Manby1
1Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
2London Centre for Nanotechnology, UCL, London WC1H 0AH, United Kingdom
3Department of Physics and Astronomy, UCL, London WC1E 6BT, United Kingdom
4Department of Earth Sciences, UCL, London WC1E 6BT, United Kingdom
Received 2 July 2009; revised manuscript received 9 September 2009; published 5 October 2009
The lattice parameter, bulk modulus, and cohesive energy of lithium hydride are calculated to very high
accuracy through a combination of periodic and finitecluster electronic structure calculations. The Hartree
Fock contributions are taken from earlier work in which planewave calculations were corrected for pseudo
potential errors. Molecular electronic structure calculations on finite clusters are then used to compute the
correlation contributions and finitesize effects are removed through the hierarchical scheme. The systematic
improvability of the molecular electronic structure methods makes it possible to converge the static cohesive
energy to within a few tenths of a millihartree. Zeropoint energy contributions are determined from density
functional theory phonon frequencies. All calculated properties of lithium hydride and deuteride agree with
empirical observations to within experimental uncertainty.
DOI: 10.1103/PhysRevB.80.165109 PACS number s : 71.15.Nc, 31.15.bw, 61.50.Lt
I. INTRODUCTION
Computational studies of crystalline solids are dominated
by density functional theory DFT; see, for example, Ref. 1 ,
