Linked Life Data

21190320

Source:http://linkedlifedata.com/resource/pubmed/id/21190320

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2011-1-27
pubmed:abstractText
We investigate a term-by-term scaling of the second-order energy correction obtained by perturbation theory (PT) starting from a multiconfiguration wave function. The total second-order correction is decomposed into several terms, based on the level and the spin pattern of the excitations. To define individual terms, we extend the same spin/different spin categorization of spin component scaling in various ways. When needed, identification of the excitation level is facilitated by the pivot determinant underlying the multiconfiguration PT framework. Scaling factors are determined from the stationary condition of the total energy calculated up to order 3. The decomposition schemes are tested numerically on the example of bond dissociation profiles and energy differences. We conclude that Grimme's parameters determined for single-reference Møller-Plesset theory may give a modest error reduction along the entire potential surface, if adopting a multireference based PT formulation. Scaling factors obtained from the stationary condition show relatively large variation with molecular geometry, at the same time they are more efficient in reducing the error when following a bond dissociation process.
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Feb
pubmed:issn
1520-5215
pubmed:author
pubmed:issnType
Electronic
pubmed:day
3
pubmed:volume
115
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
523-34
pubmed:year
2011
pubmed:articleTitle
Spin component scaling in multiconfiguration perturbation theory.
pubmed:affiliation
Laboratory of Theoretical Chemistry, Institute of Chemistry, Loránd Eötvös University, H-1518 Budapest, POB 32, Hungary. szabados@chem.elte.hu
pubmed:publicationType
Journal Article