Theoretical and numerical assessments of spin-flip time-dependent   density functional theory

doi:10.1063/1.3676736

CORC > 北京大学 > 化学与分子工程学院

	Theoretical and numerical assessments of spin-flip time-dependent density functional theory
	Li, Zhendong ; Liu, Wenjian
刊名	journal of chemical physics
	2012
关键词	COUPLED-CLUSTER METHODS INCLUDING TRIPLE EXCITATIONS TAMM-DANCOFF APPROXIMATION GAUSSIAN BASIS FUNCTIONS SELF-CONSISTENT-FIELD ATOMIC BASIS SETS FIRST-ROW ATOMS EXCITED-STATES MOLECULAR CALCULATIONS BOND-BREAKING
DOI	10.1063/1.3676736
英文摘要	Spin-flip time-dependent density functional theory (SF-TD-DFT) with the full noncollinear hybrid exchange-correlation kernel and its approximate variants are critically assessed, both formally and numerically. As demonstrated by the ethylene torsion and the C-2v ring-opening of oxirane, SF-TD-DFT is very useful for describing nearly degenerate situations. However, it may occasionally yield unphysical results. This stems from the noncollinear form of the generalized gradient approximation, which becomes numerically instable in the presence of spin-flip excitations from the closed-to vacant-shell orbitals of an open-shell reference. To cure this defect, a simple modification, dubbed as ALDA0, is proposed in the spirit of adiabatic local density approximation (ALDA). It is applicable to all kinds of density functionals and yields stable results without too much loss of accuracy. In particular, the combination of ALDA0 with the Tamm-Dancoff approximation is a promising tool for studying global potential energy surfaces. In addition to the kernel problem, SF-TD-DFT is also rather sensitive to the choice of reference states, as demonstrated by the spin multiplet states of closed-shell molecules of H2O, CH2O, and C2H4. Surprisingly, SF-TD-DFT with pure density functionals may also fail for valance excitations with large orbital overlaps, at variance with the spin-conserving counterpart (SC-TD-DFT). In this case, the inclusion of a large amount of Hartree-Fock exchange is mandatory for quantitative results. Nonetheless, for spatially degenerate cases such as CF, CH, and NH+, SF-TD-DFT is more advantageous than SC-TD-DFT, unless the latter is also space adapted. These findings are very instructive for future development and applications of TD-DFT. (C) 2012 American Institute of Physics. [doi:10.1063/1.3676736]; Physics, Atomic, Molecular & Chemical; SCI(E); EI; 0; ARTICLE; 2; 136
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/235243]
专题	化学与分子工程学院
推荐引用方式 GB/T 7714	Li, Zhendong,Liu, Wenjian. Theoretical and numerical assessments of spin-flip time-dependent density functional theory[J]. journal of chemical physics,2012.
APA	Li, Zhendong,&Liu, Wenjian.(2012).Theoretical and numerical assessments of spin-flip time-dependent density functional theory.journal of chemical physics.
MLA	Li, Zhendong,et al."Theoretical and numerical assessments of spin-flip time-dependent density functional theory".journal of chemical physics (2012).