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Selective configuration interaction methods approximate correlated molecular ground- and excited states by considering only the most relevant Slater determinants in the expansion. While a recently proposed neural-network-assisted approach…

The study of isolated defects in solids is a natural target for classical or quantum embedding methods that treat the defect at a high level of theory and the rest of the solid at a lower level of theory. Here, in the context of…

Materials Science · Physics 2023-01-25 Bryan T. G. Lau , Brian Busemeyer , Timothy C. Berkelbach

The tailored coupled cluster (TCC) approach is a promising ansatz that preserves the simplicity of single-reference coupled cluster theory, while incorporating a multi-reference wave function through amplitudes obtained from a preceding…

Chemical Physics · Physics 2021-01-07 Maximilian Mörchen , Leon Freitag , Markus Reiher

Closed-form, analytical approximations for electrostatic properties of molecules are of unique value, as these can provide computational speed, versatility, and physical insight. Here, we derive a simple, closed-form formula for the…

Chemical Physics · Physics 2022-03-14 Dan Folescu , Alexey V. Onufriev

The self-consistent theory of the correlation effects in Highly Correlated Systems(HCS) is presented. The novel Irreducible Green's Functions(IGF) method is discused in detail for the Hubbard model and random Hubbard model. The…

Strongly Correlated Electrons · Physics 2008-02-03 A. L. Kuzemsky

Approximate full configuration interaction (FCI) calculations have recently become tractable for systems of unforeseen size thanks to stochastic and adaptive approximations to the exponentially scaling FCI problem. The result of an FCI…

Strongly Correlated Electrons · Physics 2017-10-25 Susi Lehtola , Norm M. Tubman , K. Birgitta Whaley , Martin Head-Gordon

Elucidating photochemical reactions is vital to understand various biochemical phenomena and develop functional materials such as artificial photosynthesis and organic solar cells, albeit its notorious difficulty by both experiments and…

Chemical Physics · Physics 2022-01-26 Keita Omiya , Yuya O. Nakagawa , Sho Koh , Wataru Mizukami , Qi Gao , Takao Kobayashi

We present an algorithm to solve the CASSCF linear response equations that is both simple and efficient. The algorithm makes use of the well established symmetric and antisymmetric combinations of trial vectors, but further orthogonalizes…

Chemical Physics · Physics 2023-07-27 Riccardo Alessandro , Ivan Giannì , Federica Pes , Tommaso Nottoli , Filippo Lipparini

Multi-configurational wave-function theory (MC-WFT) that combines complete active space self-consistent field (CASSCF) approach with subsequent state interaction (SI) treatment of spin-orbit coupling (SOC), abbreviated as CASSCF-SO, plays…

Chemical Physics · Physics 2025-03-11 Zhe-Bin Guan , Hong Jiang

Efficient simulation of strongly correlated electrons has become a routine tool in molecular electronic structure theory due to recent advances in approximate configuration interaction (CI) techniques. Nonetheless, the quantitative and…

Quantum Physics · Physics 2026-04-06 Daniel Gibney , Anthony W Schlimgen , Jan-Niklas Boyn

Accurate many-body treatments of condensed-phase systems are challenging because correlated solvers such as full configuration interaction (FCI) and the density matrix renormalization group (DMRG) scale exponentially with system size.…

Accurately and efficiently describing strongly correlated electronic systems is a central challenge in quantum computational chemistry, with classical and quantum computers. The localized active space self-consistent field method (LASSCF)…

Robust and Real-time State of Charge (SOC) estimation is essential for Lithium Iron Phosphate (LFP) batteries, which are widely used in electric vehicles (EVs) and energy storage systems due to safety and longevity. However, the flat Open…

Systems and Control · Electrical Eng. & Systems 2025-07-03 Junzhe Shi , Shida Jiang , Shengyu Tao , Jaewong Lee , Manashita Borah , Scott Moura

Recently developed locally scaled self-interaction correction (LSIC) is a one-electron SIC method that, when used with a ratio of kinetic energy densities (z$_\sigma$) as iso-orbital indicator, performs remarkably well for both…

Chemical Physics · Physics 2024-01-31 Rajendra R. Zope , Yoh Yamamoto , Tunna Baruah

We present systematic and comprehensive correlated-electron calculations of the linear photoabsorption spectra of small neutral closed- and open-shell sodium clusters (Na_{n}, n=2-6), as well as closed-shell cation clusters (Na_{n}^{+},…

Atomic and Molecular Clusters · Physics 2017-05-25 Pradip Kumar Priya , Deepak Kumar Rai , Alok Shukla

We present NECI, a state-of-the-art implementation of the Full Configuration Interaction Quantum Monte Carlo algorithm, a method based on a stochastic application of the Hamiltonian matrix on a sparse sampling of the wave function. The…

In this work, we present a time-dependent (TD) selected configuration interaction method based on our recently-introduced adaptive configuration interaction (ACI). We show that ACI, in either its ground or excited state formalisms, is…

Chemical Physics · Physics 2020-01-08 Jeffrey B. Schriber , Francesco A. Evangelista

The Perdew-Zunger self-interaction correction(PZ-SIC) improves the performance of density functional approximations(DFAs) for the properties that involve significant self-interaction error(SIE), as in stretched bond situations, but…

A multiconfigurational adiabatic connection (AC) formalism is an attractive approach to computing dynamic correlation within CASSCF and DMRG models. Practical realizations of AC have been based on two approximations: i) fixing one- and…

Chemical Physics · Physics 2023-02-15 Mikuláš Matoušek , Michał Hapka , Libor Veis , Katarzyna Pernal

Fermi-L\"owdin orbital self-interaction-correction (FLOSIC) method uses symmetric orthogonalized Fermi orbitals as localized orbitals in one-electron SIC schemes. In FLOSIC, a set of Fermi orbital descriptors (FOD) that define the FLOs is…

Chemical Physics · Physics 2025-08-08 Selim Romero , Yoh Yamamoto , Tunna Baruah , Rajendra R. Zope