New approaches to study excited states in density functional theory: general discussion

Brandenburg, Jan Gerit; Burke, Kieron; Fromager, Emmanuel; Gatti, Matteo; Giarrusso, Sara; Gidopoulos, Nikitas I.; Gori‐Giorgi, Paola; Gowland, Duncan; Helgaker, Trygve; Hodgson, M. J. P.; Lacombe, Lionel; Levi, Gianluca; Loos, Pierre‐François; Maitra, Neepa T.; Morais, Eduardo Maurina; Mehta, Nisha; Monti, Fiorella; Mulay, Manasi R.; Pernal, Katarzyna; Reining, Lucia; Ryder, Matthew R.; Savin, Andreas; Sirbu, Dumitru; Teale, Andrew M.; Thom, Alex J. W.; Truhlar, Donald G.; Wetherell, Jack; Yang, Weitao

doi:10.1039/d0fd90026e

Cited by 5 publications

(3 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For DFT references, this is done along the adiabatic connection curve, and the procedure is described in Ref. (23) (see also discussion (24)).…”

Section: Double Excitationsmentioning

confidence: 99%

Double and Charge-Transfer Excitations in Time-Dependent Density Functional Theory

Maitra¹

2021

Preprint

Self Cite

View full text Add to dashboard Cite

Time-dependent density functional theory has emerged as a method of choice for calculations of spectra and response properties in physics, chemistry, and biology, with its system-size scaling enabling computations on systems much larger than possible otherwise. While increasingly complex and interesting systems have been successfully tackled with relatively simple functional approximations, there has also been increasing awareness that these functionals tend to fail for certain classes of approximations. I review the fundamental challenges the approximate functionals have in describing double-excitations and charge-transfer excitations, which are two of the most common impediments for the theory to be applied in a black box way. At the same time, I describe the progress made in recent decades in developing functional approximations that give useful predictions for these excitations.

show abstract

“…For DFT references, this is done along the adiabatic connection curve, and the procedure is described in Ref. (23) (see also discussion (24)).…”

Section: Double Excitationsmentioning

confidence: 99%

Double and Charge-Transfer Excitations in Time-Dependent Density Functional Theory

Maitra¹

2021

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…Recently, there has been a lot of effervescence towards excited states and different flavours of DFT that can describe them [40]. While time-dependent DFT is still a very popular method [41][42][43][44], most calculations are performed using an adiabatic approximation, in which the instantaneous density is fed into a ground-state functional.…”

Section: Introductionmentioning

confidence: 99%

Electronic vector potential from the exact factorization of a complex wavefunction

Giarrusso,

Gori-Giorgi,

Agostini

2024

Preprint

View full text Add to dashboard Cite

We generalize the definitions of local scalar potentials named vkin and vN−1, which are relevant to properly describe phenomena such as molecular dissociation with density-functional theory, to the case in which the electronic wavefunction corresponds to a complex current-carrying state. In such a case, an extra term in the form of a vector potential appears which cannot be gauged away. Both scalar and vector potentials are introduced via the exact factorization formalism which allows to expand the given Schrödinger equation in two coupled equations, one for the marginal and one for the conditional amplitude. The electronic vector potential is directly related to the paramagnetic current density carried by the total wavefunction and to the diamagnetic current density in the equation for the marginal amplitude. An explicit example of this vector potential in a triplet state of two non-interacting electrons is showcased together with its associated circulation, giving rise to a non-vanishing geometric phase. Some connections with the exact factorization for the full molecular wavefunction beyond the Born-Oppenheimer approximation are also discussed.

show abstract

“…Before proceeding, we note that there are various extensions of KS-DFT targeted for open-shell systems. For example, we mention the restricted open-shell KS (ROKS) method 12,13 , KS-DFT with complex, spin-restricted KS orbitals 14 and the recent progress in ensemble DFT for degenerate/excited states [15][16][17][18][19][20] . Methods with multi-determinant KS reference states, or using ensemble DFT, are indeed intrinsically advantageous for open-shell systems.…”

Section: Introductionmentioning

confidence: 99%

Density functionals with spin-density accuracy for open shells

Callow

Pearce

Gidopoulos

2022

The Journal of Chemical Physics

Self Cite

View full text Add to dashboard Cite

Electrons in zero external magnetic field can be studied with density functional theory (DFT) or with spin-DFT (SDFT). The latter is normally used for open shell systems because its approximations appear to model better the exchange and correlation (xc) functional, but also because so far the application of DFT implied a closed-shell-like approximation. Correcting this error for open shells allows the approximate DFT xc functionals to become as accurate as those in SDFT. In the limit of zero magnetic field, the Kohn-Sham equations of SDFT emerge as the generalised KS equations of DFT.

show abstract

New approaches to study excited states in density functional theory: general discussion

Cited by 5 publications

References 4 publications

Double and Charge-Transfer Excitations in Time-Dependent Density Functional Theory

Double and Charge-Transfer Excitations in Time-Dependent Density Functional Theory

Electronic vector potential from the exact factorization of a complex wavefunction

Density functionals with spin-density accuracy for open shells

Contact Info

Product

Resources

About