Assessment of simple and intuitive semiempirical approximations for non-adiabatic coupling vectors in the frame of (LC)-TDDFTB

Humeniuk, Alexander; Mitrić, Roland

doi:10.48550/arxiv.1908.00276

Cited by 1 publication

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References 13 publications

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“…Though analytical derivative couplings between ground and excited states [18,19,20,21,22,23,24,25] and later also between excited states [26,27,28,29] have been published for TD-DFT, no such derivation exists for TD-DFTB. (For attempts to approximate TD-DFTB couplings see [30]). This does not impede SH simulations, as most implementations require only scalar time-derivative couplings σ(t) = Ψ I |∂/∂t|Ψ J = d IJ • ξ, which can be computed by numerical differentiation without explicit recourse to d IJ .…”

Section: Introductionmentioning

confidence: 99%

Ground-to-excited derivative couplings for the density functional based tight-binding method: Semi-local and long-range corrected formulations

Niehaus¹

2020

Preprint

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A derivation of non-adiabatic coupling vectors for the density functional based tight binding method (DFTB) between ground and excited states is presented. The analytical result is valid both for semi-local and long-range corrected DFTB and includes all required Pulay terms. Electron-translation factors lead to a conceptual simplification of the Slater-Koster scheme for precomputed integrals. Compared to scalar couplings obtained from numerical derivatives, the present approach is computationally more efficient and can be applied to systems with hundreds of atoms. The accuracy of DFTB derivative couplings is assessed by comparison to full density functional theory (DFT) calculations using semi-local and hybrid exchange-correlation functionals with promising results. As exemplified by a case study of furan, DFTB provides non-adiabatic coupling vectors that are close to DFT counterparts in size and direction also in the vicinity of conical intersections.

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Section: Introductionmentioning

confidence: 99%

Ground-to-excited derivative couplings for the density functional based tight-binding method: Semi-local and long-range corrected formulations

Niehaus¹

2020

Preprint

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Assessment of simple and intuitive semiempirical approximations for non-adiabatic coupling vectors in the frame of (LC)-TDDFTB

Abstract: In this study, two different simple and intuitive semiempirical schemes for computing approximate non-adiabatic coupling vectors (NACVs) between the ground and excited electronic states are presented. The first approximation makes use of Mulliken

Cited by 1 publication

References 13 publications

Ground-to-excited derivative couplings for the density functional based tight-binding method: Semi-local and long-range corrected formulations

Ground-to-excited derivative couplings for the density functional based tight-binding method: Semi-local and long-range corrected formulations

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