MP2.X: a generalized MP2.5 method that produces improved binding energies with smaller basis sets

0370164 - ÚOCHB 2012 RIV GB eng J - Journal Article
Riley, Kevin Eugene - Řezáč, Jan - Hobza, Pavel
MP2.X: a generalized MP2.5 method that produces improved binding energies with smaller basis sets.
Physical Chemistry Chemical Physics. Roč. 13, č. 47 (2011), s. 21121-21125. ISSN 1463-9076. E-ISSN 1463-9084
R&D Projects: GA MŠMT LC512
Grant - others:European Social Fund(XE) CZ.1.05/2.1.00/03.0058
Institutional research plan: CEZ:AV0Z40550506
Keywords : Plesset perturbation-theory * stacking * pairs * spin
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 3.573, year: 2011

In this article we present binding energy results for a scaled MP2.5 method along with several basis sets. The accuracy of the methods tested here is determined by comparison to reference data in the newly developed S66 data set of interaction energies. It is found that scaling of the MP2.5 correction term results in strongly improved binding energies for small basis sets, such as 6-31G* and 6-311++G**. The scaling parameter for larger basis sets, such as aug-cc-pVDZ and aug-cc-pVTZ, approaches a value of 0.50, which corresponds to the original (unparametrized) MP2.5 method. It is found that the MP2.X method yields S66 RMS errors of approximately 0.15 kcal mol 1 for all basis sets. In addition to generally providing more accurate binding energies than MP2.5, MP2.X generally produces a more well-balanced description of noncovalent interactions, yielding better binding energies for dispersion-bound and mixed dispersionelectrostatic complexes.
Permanent Link: http://hdl.handle.net/11104/0204043