Locally Range-Separated Local Hybrid Functionals – The Next Level on the Hybrid Functional Ladder

Published: March 27, 2023

In this work, the new class of locally range-separated local hybrid (LRSLH) functionals is presented. LRSLH combine concepts a exact-exchange admixture as in hybrids with functionals. The satisfiability important theoretical constraints on by approach discussed comparison to existing functional classes proposing categorization scheme for functionals, labeled ladder. particular, concerns iso-orbital and asymptotic potential limits well high-density limit respect uniform coordinate scaling gradient expansion exchange energy density, which contrast schemes can be simultaneously satisfied Furthermore, work provides first explorative study regarding performance approach. Despite featuring only up two empirical parameters, optimized exhibit similar atomization energies transition barrier heights some more recent highlights great

Language: Английский

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Natural virtual orbitals for the GW method in the random-phase approximation and beyond

The Journal of Chemical Physics, Journal Year: 2023, Volume and Issue: 158(14)

Published: April 10, 2023

The increasingly popular GW method is becoming a convenient tool to determine vertical ionization energies in molecular systems. However, depending on the formalism used and range of orbitals investigated, it may be hampered by steep computational scaling. To alleviate this issue, correlated natural virtual (NVOs) based second-order Møller-Plesset (MP2) direct MP2 correlation are implemented, resulting NVOs tested quasiparticle energies. Test cases include variants G0W0 evGW0 as well more elaborate vertex corrections. We find that for larger systems basis sets, considerably improve efficiency. Furthermore, we test performance truncated (frozen) NVO ansatz GW100 set. For latter, demonstrated that, using carefully chosen truncation threshold, lead negligible loss accuracy while providing speedups one order magnitude. compare very accurate obtained from coupled-cluster theory with singles, doubles, noniterative triples [CCSD(T)], confirming introduced truncating compared methodical errors approximation. It also choice set impacts results far than suitably space. Therefore, at same expense, can NVOs. Finally, provide improved reference CCSD(T) values set, which have been def2-QZVPP

Language: Английский

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Density functional descriptions of interfacial electronic structure

Chemical Physics Reviews, Journal Year: 2023, Volume and Issue: 4(3)

Published: Aug. 23, 2023

Heterogeneous interfaces are central to many energy-related applications in the nanoscale. From first-principles electronic structure perspective, one of outstanding problems is accurately and efficiently calculating how frontier quasiparticle levels component aligned energy with those another at interface, i.e., so-called interfacial band alignment or level alignment. The offset these phenomenologically associated charge-transfer barrier across interface therefore dictates dynamics. Although many-body perturbation theory provides a formally rigorous framework for computing structure, it often high computational cost limited by its perturbative nature. It is, therefore, great interest develop practical alternatives, preferably based on density functional (DFT), which known balance between efficiency accuracy. However, conventional developments functionals largely focus total energies thermodynamic properties, design aiming only emerging recently. This Review dedicated self-contained narrative problem efforts DFT community tackling it. Since closely related surfaces, we first discuss key physics behind surface namely, image potential gap renormalization. followed review early examinations exchange-correlation hole potential, quantities DFT. Finally, survey two modern endeavors development that dielectric-dependent hybrids local hybrids.

Language: Английский

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Exact Two-Component Theory Becoming an Efficient Tool for NMR Shieldings and Shifts with Spin-Orbit Coupling

Published: Aug. 25, 2023

We present a gauge-origin invariant exact two-component (X2C) approach within modern density functional framework, supporting meta-generalized gradient approximations (meta-GGAs) such as TPSS and range-separated hybrid functionals CAM-B3LYP. The complete exchange-correlation kernel is applied, including the direct contribution of field-dependent basis functions reorthonormalization from perturbed overlap matrix. Additionally, finite nucleus model available for electron-nucleus potential vector throughout. Efficiency ensured by diagonal local approximation to unitary decoupling transformation (DLU) in X2C well (multipole-accelerated) resolution identity Coulomb term (MARI-J, RI-J) seminumerical exchange approximation. Errors introduced these are assessed found be clearly negligible. applicability our implementation large-scale calculations demonstrated tin pincer-type system low-valent lead complexes. Here, calculation Sn NMR shifts ligand with about 2400 requires less than one hour functionals. Further, impact spin-orbit coupling on nucleus-independent chemical corresponding ring currents all-metal aromatic systems studied.

Language: Английский

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Performance of density-functional-theory and random-phase-approximation methods on the study of transition-metal clusters: the Ta _n clusters as an example

Molecular Physics, Journal Year: 2024, Volume and Issue: unknown

Published: July 1, 2024

Language: Английский

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