English
Related papers

Related papers: Large-scale relativistic complete active space sel…

200 papers

Orbital optimization procedure is widely called in electronic structure simulation. To efficiently find the orbital optimization solution, we developed a new second order orbital optimization algorithm, co-iteration augmented Hessian (CIAH)…

Chemical Physics · Physics 2017-01-11 Qiming Sun

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

We present the implementation of a quadratically convergent Self-consistent field (QCSCF) algorithm based on an adaptive trust-radius optimization scheme for restricted open-shell Hartree-Fock (ROHF), restricted Hartree-Fock (RHF), and…

Chemical Physics · Physics 2022-01-12 Tommaso Nottoli , Jürgen Gauss , Filippo Lipparini

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

In this work, we investigate the possibility of improving multireference-driven coupled cluster (CC) approaches with an algorithm that iteratively combines complete active space (CAS) calculations with tailored CC and externally corrected…

Chemical Physics · Physics 2025-03-06 Robin Feldmann , Max Mörchen , Jakub Lang , Michał Lesiuk , Markus Reiher

The Perdew-Zunger self-interaction correction cures many common problems associated with semilocal density functionals, but suffers from a size-extensivity problem when Kohn-Sham orbitals are used in the correction. Fermi-L\"{o}wdin-orbital…

Computational Physics · Physics 2017-06-30 Zeng-hui Yang , Mark R. Pederson , John P. Perdew

An accurate description of electron correlation is one of the most challenging problems in quantum chemistry. The exact electron correlation can be obtained by means of full configuration interaction (FCI). A simple strategy for…

Chemical Physics · Physics 2021-05-14 Jae Woo Park

The localized active space self consistent field (LASSCF) method factorizes a complete active space (CAS) wave function into an antisymmetrized product of localized active space wave function fragments. Correlation between fragments is then…

Chemical Physics · Physics 2024-03-26 Valay Agarawal , Daniel King , Matthew R. Hermes , Laura Gagliardi

We present a trust-region augmented Hessian implementation (TRAH-SCF) for restricted and unrestricted Hartree-Fock and Kohn-Sham methods. With TRAH-SCF convergence can always be achieved with tight convergence thresholds, which requires…

Chemical Physics · Physics 2021-05-05 Benjamin Helmich-Paris

This work presents a general framework for deriving exact and approximate Newton self-consistent field (SCF) orbital optimization algorithms by leveraging concepts borrowed from differential geometry. Within this framework, we extend the…

Chemical Physics · Physics 2023-09-13 Robin Feldmann , Alberto Baiardi , Markus Reiher

We report the derivation and implementation of orbital optimization algorithms for the active space decomposition (ASD) model, which are extensions of complete active space self-consistent field (CASSCF) and its occupation-restricted…

Chemical Physics · Physics 2015-08-17 Inkoo Kim , Shane M. Parker , Toru Shiozaki

We present the time-dependent restricted-active-space self-consistent field (TD-RASSCF) theory as a new framework for the time-dependent many-electron problem. The theory generalizes the multiconfigurational time-dependent Hartree-Fock…

Atomic Physics · Physics 2014-05-22 Haruhide Miyagi , Lars Bojer Madsen

We describe the time-dependent restricted-active-space self-consistent-field (TD-RASSCF) method for a system of interacting bosons. We provide the theory of the method and discuss its numerical implementation. The method provides a general…

Quantum Physics · Physics 2017-04-28 Camille Lévêque , Lars Bojer Madsen

We present IAS15, a 15th-order integrator to simulate gravitational dynamics. The integrator is based on a Gau\ss-Radau quadrature and can handle conservative as well as non-conservative forces. We develop a step-size control that can…

Earth and Planetary Astrophysics · Physics 2015-06-22 Hanno Rein , David S. Spiegel

We present an algorithm and its parallel implementation for solving a self consistent problem as encountered in Hartree Fock or Density Functional Theory. The algorithm takes advantage of the sparsity of matrices through the use of local…

Chemical Physics · Physics 2016-07-25 Anthony Scemama , Nicolas Renon , Mathias Rapacioli

We present a Gaussian-basis implementation of orbital-free density-functional theory (OF-DFT) in which the trust-region image method (TRIM) is used for optimization. This second-order optimization scheme has been constructed to provide…

Chemical Physics · Physics 2021-09-15 Matthew S. Ryley , Michael Withnall , Tom J. P. Irons , Trygve Helgaker , Andrew M. Teale

We present a numerical implementation of the infinite-range exterior complex scaling (irECS) [Phys. Rev. A 81, 053845 (2010)] as an efficient absorbing boundary to the time-dependent complete-active-space self-consistent field (TD-CASSCF)…

Atomic Physics · Physics 2018-03-07 Yuki Orimo , Takeshi Sato , Armin Scrinzi , Kenichi L. Ishikawa

Density fitting (DF), also known as the resolution of the identity (RI), is a widely used technique in quantum chemical calculations with various types of atomic basis sets - Gaussian-type orbitals, Slater-type orbitals, as well as…

Chemical Physics · Physics 2021-12-22 Susi Lehtola

Full charge self-consistence (CSC) over the electron density has been implemented into the local density approximation plus dynamical mean-field theory (LDA+DMFT) scheme based on a full-potential linear muffin-tin orbital method (FP-LMTO).…

Strongly Correlated Electrons · Physics 2014-08-07 O. Grånäs , I. Di Marco , P. Thunström , L Nordström , O. Eriksson , T. Björkman , J. M. Wills

In this contribution, we present the implementation of a second-order CASSCF algorithm in conjunction with the Cholesky decomposition of the two-electron repulsion integrals. The algorithm, called Norm-Extended Optimization, guarantees…

Chemical Physics · Physics 2021-04-09 Tommaso Nottoli , Jürgen Gauss , Filippo Lipparini