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Related papers: Cheap and near exact CASSCF with large active spac…

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We present a new efficient way to perform hybrid density functional theory (DFT) based electronic structure calculation. The new method uses an interpolative separable density fitting (ISDF) procedure to construct a set of numerical…

Computational Physics · Physics 2017-07-31 Wei Hu , Lin Lin , Chao Yang

The Configuration Interaction (CI) method using orbitals centered on the nucleus has recently been applied to calculate the interactions of positrons interacting with atoms. Computational investigations of the convergence properties of…

Atomic Physics · Physics 2007-05-23 J. Mitroy , M. W. J. Bromley

For many-body methods such as MCSCF and CASSCF, in which the number of one-electron orbitals are optimized and independent of basis set used, there are no problems with using plane-wave basis sets. However, for methods currently used in…

Computational Physics · Physics 2020-09-02 Eric J. Bylaska , Duo Song , Nicholas P. Bauman , Karol Kowalski , Daniel Claudino , Travis S. Humble

We derive and implement analytic nuclear gradients and derivative couplings for a constrained Complete Active Space Self-Consistent Field with a small active space designed to model electron or hole transfer. Using a Lagrangian formalism,…

Computational Physics · Physics 2025-09-01 Tian Qiu , Joseph E. Subotnik

The exponential scaling of complete active space (CAS) and full configuration interaction (CI) calculations limits the ability of quantum chemists to simulate the electronic structures of strongly correlated systems. Herein, we present…

Chemical Physics · Physics 2024-08-01 Kenneth O. Berard , Hongji Gao , Alexander Teplukhin , Xiangmin Jiao , Benjamin G. Levine

[Background] Single-reference density functional theory is very successful in reproducing bulk nuclear properties like binding energies, radii, or quadrupole moments throughout the entire periodic table. Its extension to the multi-reference…

Nuclear Theory · Physics 2017-01-30 W. Satula , P. Baczyk , J. Dobaczewski , M. Konieczka

In a recent work, we introduced the foundations of an orthogonally constrained complete active space self-consistent field (OC-CASSCF) framework that produces state-specific molecular orbitals for mutually orthogonal multiconfigurational…

Chemical Physics · Physics 2026-01-28 Loris Delafosse , Vincent Robert , Saad Yalouz

We investigate configuration-interaction (CI) calculations on a basis of molecular orbitals generated by preliminary density-functional theory (DFT) calculations. We use this CI/DFT framework to improve the modeling of core-excited states…

Chemical Physics · Physics 2025-09-11 Giorgio Visentin , Francois Mauger

Finite element methods based on cut-cells are becoming increasingly popular because of their advantages over formulations based on body-fitted meshes for problems with moving interfaces. In such methods, the cells (or elements) which are…

Computational Engineering, Finance, and Science · Computer Science 2022-07-18 Chennakesava Kadapa , Xinyu Wang , Yue Mei

The general procedure underlying Hartree-Fock and Kohn-Sham density functional theory calculations consists in optimizing orbitals for a self-consistent solution of the Roothaan-Hall equations in an iterative process. It is often ignored…

Chemical Physics · Physics 2017-03-16 Alain C. Vaucher , Markus Reiher

The combination of density functional theory (DFT) with a multiconfigurational wave function is an efficient way to include dynamical correlation in calculations with multiconfiguration self-consistent field wave functions. These methods…

Chemical Physics · Physics 2018-02-14 Geng Dong , Ulf Ryde , Hans Jørgen Aa. Jensen , Erik D. Hedegård

Recently proposed local self-interaction correction (LSIC) method [Zope, R. R. et al., J. Chem. Phys. 151, 214108 (2019)] is a one-electron self-interaction-correction (SIC) method that uses an iso-orbital indicator to apply the SIC at each…

Chemical Physics · Physics 2023-02-22 Yoh Yamamoto , Tunna Baruah , Po-Hao Chang , Selim Romero , Rajendra R. Zope

Selected configuration interaction (sCI) methods including second-order perturbative corrections provide near full CI (FCI) quality energies with only a small fraction of the determinants of the FCI space. Here, we introduce both a…

Chemical Physics · Physics 2018-08-09 Yann Garniron , Anthony Scemama , Emmanuel Giner , Michel Caffarel , Pierre-François Loos

In this paper, we present an efficient, accurate and fully Lagrangian numerical solver for modeling wave interaction with oscillating wave energy converter (OWSC). The key idea is to couple SPHinXsys, an open-source multi-physics library in…

Fluid Dynamics · Physics 2020-12-11 Chi Zhang , Yanji Wei , Frederic Dias , Xiangyu Hu

We have combined our adaptive configuration interaction (ACI) [J.B. Schriber and F.A. Evangelista, J. Chem. Phys. 144, 161106 (2016)] with a density-fitted implementation of the second-order perturbative multireference driven similarity…

Chemical Physics · Physics 2018-08-29 Jeffrey B. Schriber , Kevin P. Hannon , Francesco A. Evangelista

One-body reduced density matrix functional theory (RDMFT) provides an alternative to Density Functional Theory (DFT), able to treat static correlation while keeping a relatively low computation scaling. Its disadvantageous cost comes mainly…

Chemical Physics · Physics 2024-05-07 Nicolas G. Cartier , Klaas J. H. Giesbertz

In the pursuit of accurate descriptions of strongly correlated quantum many-body systems, dynamical mean-field theory (DMFT) has been an invaluable tool for elucidating the spectral properties and quantum phases of both phenomenological…

Strongly Correlated Electrons · Physics 2019-10-07 Carlos Mejuto-Zaera , Norm M. Tubman , K. Birgitta Whaley

We derive analytical nuclear gradients for state-averaged orbital-optimized configuration interaction singles (SACIS) and its spin-projected extension (SAECIS), enabling efficient geometry optimization and minimum-energy conical…

Chemical Physics · Physics 2026-04-15 Takashi Tsuchimochi

We present a quantum-classical hybrid algorithm for calculating the ground state and its energy of the quantum many-body Hamiltonian by proposing an adaptive construction of a quantum state for the quantum-selected configuration interaction…

Quantum Physics · Physics 2024-12-12 Yuya O. Nakagawa , Masahiko Kamoshita , Wataru Mizukami , Shotaro Sudo , Yu-ya Ohnishi

The multiconfiguration Dirac-Hartree-Fock (MCDHF) and relativistic configuration interaction (RCI) methods are used to provide excitation energies, radiative transition data, lifetimes, Lande g-factors, hyperfine interaction constants and…