21721606

Source:http://linkedlifedata.com/resource/pubmed/id/21721606

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Predicate	Object
rdf:type	pubmed:Citation
lifeskim:mentions	umls-concept:C0013850, umls-concept:C0025663, umls-concept:C0185125, umls-concept:C0205246, umls-concept:C0549255, umls-concept:C1442792
pubmed:issue	24
pubmed:dateCreated	2011-7-4
pubmed:abstractText	The solution of the time-dependent Schro?dinger equation for systems of interacting electrons is generally a prohibitive task, for which approximate methods are necessary. Popular approaches, such as the time-dependent Hartree-Fock (TDHF) approximation and time-dependent density functional theory (TDDFT), are essentially single-configurational schemes. TDHF is by construction incapable of fully accounting for the excited character of the electronic states involved in many physical processes of interest; TDDFT, although exact in principle, is limited by the currently available exchange-correlation functionals. On the other hand, multiconfigurational methods, such as the multiconfigurational time-dependent Hartree-Fock (MCTDHF) approach, provide an accurate description of the excited states and can be systematically improved. However, the computational cost becomes prohibitive as the number of degrees of freedom increases, and thus, at present, the MCTDHF method is only practical for few-electron systems. In this work, we propose an alternative approach which effectively establishes a compromise between efficiency and accuracy, by retaining the smallest possible number of configurations that catches the essential features of the electronic wavefunction. Based on a time-dependent variational principle, we derive the MCTDHF working equation for a multiconfigurational expansion with fixed coefficients and specialise to the case of general open-shell states, which are relevant for many physical processes of interest.
pubmed:language	eng
pubmed:journal	http://linkedlifedata.com/resource/pubmed/journal/0375360
pubmed:citationSubset	IM
pubmed:status	MEDLINE
pubmed:month	Jun
pubmed:issn	1089-7690
pubmed:author	pubmed-author:FisherA JAJ, pubmed-author:HorsfieldA PAP, pubmed-author:MirandaR PRP, pubmed-author:StellaLL
pubmed:issnType	Electronic
pubmed:day	28
pubmed:volume	134
pubmed:owner	NLM
pubmed:authorsComplete	Y
pubmed:pagination	244101
pubmed:meshHeading	pubmed-meshheading:21721606-Algorithms, pubmed-meshheading:21721606-Electrons, pubmed-meshheading:21721606-Quantum Theory, pubmed-meshheading:21721606-Time Factors
pubmed:year	2011
pubmed:articleTitle	A multiconfigurational time-dependent Hartree-Fock method for excited electronic states. I. General formalism and application to open-shell states.
pubmed:affiliation	UCL Department of Physics and Astronomy, University College London, London, United Kingdom. r.miranda@ucl.ac.uk
pubmed:publicationType	Journal Article, Research Support, Non-U.S. Gov't