TY - JOUR
T1 - Weight dependence of local exchange-correlation functionals in ensemble density-functional theory
T2 - Double excitations in two-electron systems
AU - Marut, Clotilde
AU - Senjean, Bruno
AU - Fromager, Emmanuel
AU - Loos, Pierre François
PY - 2020/12/1
Y1 - 2020/12/1
N2 - Gross-Oliveira-Kohn (GOK) ensemble density-functional theory (GOK-DFT) is a time-independent extension of density-functional theory (DFT) which allows the computation of excited-state energies via the derivatives of the ensemble energy with respect to the ensemble weights. Contrary to the time-dependent version of DFT (TD-DFT), double excitations can be easily computed within GOK-DFT. However, to take full advantage of this formalism, one must have access to a weight-dependent exchange-correlation functional in order to model the infamous ensemble derivative contribution to the excitation energies. In the present article, we discuss the construction of first-rung (i.e., local) weight-dependent exchange-correlation density-functional approximations for two-electron atomic and molecular systems (He and H2) specifically designed for the computation of double excitations within GOK-DFT. In the spirit of optimally-tuned range-separated hybrid functionals, a two-step system-dependent procedure is proposed to obtain accurate energies associated with double excitations.
AB - Gross-Oliveira-Kohn (GOK) ensemble density-functional theory (GOK-DFT) is a time-independent extension of density-functional theory (DFT) which allows the computation of excited-state energies via the derivatives of the ensemble energy with respect to the ensemble weights. Contrary to the time-dependent version of DFT (TD-DFT), double excitations can be easily computed within GOK-DFT. However, to take full advantage of this formalism, one must have access to a weight-dependent exchange-correlation functional in order to model the infamous ensemble derivative contribution to the excitation energies. In the present article, we discuss the construction of first-rung (i.e., local) weight-dependent exchange-correlation density-functional approximations for two-electron atomic and molecular systems (He and H2) specifically designed for the computation of double excitations within GOK-DFT. In the spirit of optimally-tuned range-separated hybrid functionals, a two-step system-dependent procedure is proposed to obtain accurate energies associated with double excitations.
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U2 - 10.1039/d0fd00059k
DO - 10.1039/d0fd00059k
M3 - Article
C2 - 32910116
AN - SCOPUS:85096139000
SN - 1359-6640
VL - 224
SP - 402
EP - 423
JO - Faraday Discussions
JF - Faraday Discussions
ER -