Communication: An inexpensive, variational, almost black-box, almost size-consistent correction to configuration interaction singles for valence excited states.

Autor:	Liu, Xinle, Ou, Qi, Alguire, Ethan, Subotnik, Joseph E.
Předmět:	EXCITED states QUALITATIVE chemical analysis ALGORITHMS MOLECULAR orbitals COMPUTATIONAL chemistry PREDICTION models
Zdroj:	Journal of Chemical Physics; Jun2013, Vol. 138 Issue 22, p221105-221105-4, 1p, 1 Chart, 2 Graphs
Abstrakt:	Configuration interaction singles (CIS) describe excited electronic states only qualitatively and improvements are imperative as a means of recovering chemical accuracy. In particular, variational improvements would be ideal to account for state crossings and electronic relaxation. To accomplish such an objective, in this communication we present a new suite of algorithms, abbreviated VOO-CIS for variationally orbital optimized CIS. We show below that VOO-CIS yields a uniform improvement to CIS, rebalancing the energies of CT states versus non-CT states within the same framework. Furthermore, VOO-CIS finds energetic corrections for CT states that are even larger than those predicted by CIS(D). The computational cost of VOO-CIS depends strongly on the number of excited states requested (n), but otherwise should be proportional to the cost of CIS itself. [ABSTRACT FROM AUTHOR]
Databáze:	Complementary Index
Externí odkaz:	Zobrazit plný text záznamu