Chemical Physics Letters, Vol.465, No.1-3, 136-141, 2008
Incremental expansions for SCF interaction energies: A comparison for hydrogen-bonded clusters
We present an analysis of several types of embedding potentials for use within incremental expansions of SCF interaction energies. The test set comprises hydrogen-bonded clusters (water, ammonia, methanol). It is shown that an expansion up to two-body terms is sufficient for high accuracy, in all cases, as long as the environment is described by accurate embedded-monomer Coulomb and exchange potentials. A two-body expansion with atom-centered point charges for embedding leads to larger errors, but the relative differences are kept within bounds; inclusion of three-body terms often overcompensates the deviations at the two-body level, due to basis set superposition effects. (c) 2008 Elsevier B.V. All rights reserved.