 
Summary: Extension of molecular electronic structure methods to the solid state:
computation of the cohesive energy of lithium hydride
F. R. Manby,*a
D. Alfe` bcd
and M. J. Gillancd
Received 20th September 2006, Accepted 2nd October 2006
First published as an Advance Article on the web 10th October 2006
DOI: 10.1039/b613676a
We describe a simple strategy for calculating the cohesive energy
of certain kinds of crystal using readily available quantum
chemistry techniques. The strategy involves the calculation of
the electron correlation energies of a hierarchy of free clusters,
and the cohesive energy Ecoh is extracted from the constant of
proportionality between these correlation energies and the num
ber of atoms in the limit of large clusters. We apply the strategy
to the LiH crystal, using the MP2 and CCSD(T) schemes for the
correlation energy, and show that for this material Ecoh can be
obtained to an accuracy of B30 meV per ion pair. Comparison
with the experimental value, after correction for zeropoint
energy, confirms this accuracy.
