QUEST#4X: An Extension of QUEST#4 for Benchmarking Multireference Wave Function Methods

Journal of Chemical Theory and Computation, Год журнала: 2025, Номер unknown

Опубликована: Янв. 28, 2025

Given a number of data sets for evaluating the performance single reference methods low-lying excited states closed-shell molecules, comprehensive set assessing multireference open-shell systems is still lacking. For this reason, we propose an extension (QUEST#4X) radical subset QUEST#4 (J. Chem. Theory Comput. 2020, 16, 3720) to cover 110 doublet and 39 quartet states. Near-exact results obtained by iterative configuration interaction with selection second-order perturbation correction (iCIPT2) are taken as benchmark calibrate static-dynamic-static (SDSCI) theory (SDSPT2), which minimal MRCI CI-like theory, respectively. It found that SDSCI very close in accuracy internally contracted singles doubles (ic-MRCISD), although its computational cost just one iteration latter. Unlike most variants MRPT2, SDSPT2 treats multiple same way performs similarly multistate n-electron valence (MS-NEVPT2). These findings put on firm basis.

Язык: Английский

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Reference Energies for Double Excitations: Improvement and Extension

Journal of Chemical Theory and Computation, Год журнала: 2024, Номер 20(13), С. 5655 - 5678

Опубликована: Июнь 17, 2024

In the realm of photochemistry, significance double excitations (also known as doubly excited states), where two electrons are concurrently elevated to higher energy levels, lies in their involvement key electronic transitions essential light-induced chemical reactions well challenging nature from computational theoretical chemistry point view. Based on state-of-the-art structure methods (such high-order coupled-cluster, selected configuration interaction, and multiconfigurational methods), we improve expand our prior set accurate reference excitation energies for states exhibiting a substantial amount [Loos et al. J. Chem. Theory Comput. 2019, 15, 1939]. This extended collection encompasses 47 across 26 molecular systems that separate into distinct subsets: (i) 28 "genuine" almost exclusively involve configurations (ii) 19 "partial" which exhibit more balanced character between singly configurations. For each subset, assess performance coupled-cluster (CC3, CCSDT, CC4, CCSDTQ) (CASPT2, CASPT3, PC-NEVPT2, SC-NEVPT2). Using probe percentage single involved given transition (%T1) computed at CC3 level, also propose simple correction reduces errors by factor 3, both sets excitations. We hope this complete diverse compilation will help future developments excited-state methodologies.

Язык: Английский

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The GW approximation: A quantum chemistry perspective

Advances in quantum chemistry, Год журнала: 2024, Номер unknown, С. 157 - 184

Опубликована: Янв. 1, 2024

Язык: Английский

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Finite-Size Effects in Periodic EOM-CCSD for Ionization Energies and Electron Affinities: Convergence Rate and Extrapolation to the Thermodynamic Limit

Journal of Chemical Theory and Computation, Год журнала: 2025, Номер unknown

Опубликована: Фев. 4, 2025

We investigate the convergence of quasiparticle energies for periodic systems to thermodynamic limit using increasingly large simulation cells corresponding dense integration meshes in reciprocal space. The are computed at level equation-of-motion coupled-cluster theory ionization (IP-EOM-CC) and electron attachment processes (EA-EOM-CC). By introducing an electronic correlation structure factor, expected asymptotic rates with different dimensionality formally derived. rigorously test these derivations through numerical simulations trans-polyacetylene IP/EA-EOM-CCSD G0W0@HF approximation, which confirm predicted behavior. Our findings provide a solid foundation efficient schemes correct finite-size errors calculations.

Язык: Английский

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Double ionization potential equation-of-motion coupled-cluster approach with full inclusion of 4-hole–2-particle excitations and three-body clusters

The Journal of Chemical Physics, Год журнала: 2025, Номер 162(6)

Опубликована: Фев. 10, 2025

The double ionization potential (DIP) equation-of-motion (EOM) coupled-cluster (CC) method with a full treatment of 4-hole–2-particle (4h–2p) correlations and triply excited clusters, abbreviated as DIP-EOMCCSDT(4h–2p), its approximate form called DIP-EOMCCSD(T)(a)(4h–2p) have been formulated implemented in the open-source CCpy package available on GitHub. resulting codes work both nonrelativistic spin-free scalar-relativistic Hamiltonians. By examining DIPs few small molecules, for which accurate reference data are available, we demonstrate that DIP-EOMCCSDT(4h–2p) approaches improve results obtained using DIP-EOMCC methods truncated at 3h–1p or 4h–2p excitations top CC calculations singles doubles.

Язык: Английский

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Beyond Quasi-Particle Self-Consistent GW for Molecules with Vertex Corrections

Journal of Chemical Theory and Computation, Год журнала: 2025, Номер unknown

Опубликована: Фев. 11, 2025

We introduce the ΣBSE@LBSE self-energy in quasi-particle self-consistent GW (qsGW) framework (qsΣBSE@LBSE). Here, L is two-particle response function, which we calculate by solving Bethe–Salpeter equation with static, first-order kernel. The same kernel added to Σ directly. For a set of medium organic molecules, show that including vertex both and crucial. This approach retains good performance qsGW for predicting first ionization potentials fundamental gaps, while it greatly improves description electron affinities. Its places qsΣBSE@LBSE among best-performing propagator methods charged excitations. Adding only, as commonly done solid-state community, leads devastating results affinities gaps. also test BSE@qsGW neutral charge-transfer excitation find perform similar. conclude promising approximation electronic beyond GW. hope future research on dynamical effects, second-order corrections, full self-consistency will improve accuracy this method, energies.

Язык: Английский

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Anomalous propagators and the particle-particle channel: Hedin's equations

Physical review. B./Physical review. B, Год журнала: 2024, Номер 110(11)

Опубликована: Сен. 27, 2024

Hedin's equations provide an elegant route to compute the exact one-body Green's function (or propagator) via self-consistent iteration of a set non-linear equations. Its first-order approximation, known as $GW$, corresponds resummation ring diagrams and has shown be extremely successful in physics chemistry. Systematic improvement is possible, although challenging, introduction vertex corrections. Considering anomalous propagators external pairing potential, we derive new closed equivalent famous Hedin but having approximation particle-particle (pp) $T$-matrix where one performs ladder diagrams. This pp version offers way go systematically beyond by accounting for low-order

Язык: Английский

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Anomalous propagators and the particle–particle channel: Bethe–Salpeter equation

The Journal of Chemical Physics, Год журнала: 2025, Номер 162(13)

Опубликована: Апрель 3, 2025

The Bethe-Salpeter equation has been extensively employed to compute the two-body electron-hole propagator and its poles which correspond neutral excitation energies of system. Through a different time-ordering, Green's function can also describe propagation two electrons or holes. corresponding are double ionization potentials electron affinities In this work, for particle-particle is derived within linear-response formalism using pairing field anomalous propagators. This framework allows us kernels self-energy approximations ($GW$, $T$-matrix, second-Born) as in usual case. performance these various gauged singlet triplet valence set 23 small molecules. description core hole states analyzed.

Язык: Английский

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GW Plus Cumulant Approach for Predicting Core-Level Shakeup Satellites in Large Molecules

Journal of Chemical Theory and Computation, Год журнала: 2025, Номер unknown

Опубликована: Март 3, 2025

Recently, the GW approach has emerged as a valuable tool for computing deep core-level binding energies measured in X-ray photoemission spectroscopy. However, fails to accurately predict shakeup satellite features, which arise from charge-neutral excitations accompanying ionization. In this work, we extend plus cumulant (GW + C) molecular 1s excitations, deriving conditions under C can be reliably applied processes. We present an efficient implementation with O(N4) scaling respect system size N, within all-electron framework based on numeric atom-centered orbitals. demonstrate that decoupling core and valence spaces is crucial when using localized basis functions. Additionally, meticulously validate set convergence of spectrum 65 spectral functions identify importance diffuse augmenting To assess accuracy, apply our scheme π-conjugated molecules containing up 40 atoms, predicting dominant features 0.5 eV experimental values. For acene series, benzene pentacene, how provides critical insights into interpretation experimentally observed features.

Язык: Английский

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The Amsterdam Modeling Suite

The Journal of Chemical Physics, Год журнала: 2025, Номер 162(16)

Опубликована: Апрель 22, 2025

In this paper, we present the Amsterdam Modeling Suite (AMS), a comprehensive software platform designed to support advanced molecular and materials simulations across wide range of chemical physical systems. AMS integrates cutting-edge quantum methods, including Density Functional Theory (DFT) time-dependent DFT, with mechanics, fluid thermodynamics, machine learning techniques, more, enable multi-scale modeling complex Its design philosophy allows for seamless coupling between components, facilitating that from small molecules biomolecular solid-state systems, making it versatile tool tackling interdisciplinary challenges, both in industry academia. The suite also emphasizes user accessibility, an intuitive graphical interface, extensive scripting capabilities, compatibility high-performance computing environments.

Язык: Английский

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