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Related papers: Computation of NMR shieldings at the CASSCF level …

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We report on a formulation and implementation of a scheme to compute NMR shieldings at second-order Moller-Plesset (MP2) perturbation theory using gauge-including atomic orbitals (GIAOs) to ensure gauge-origin independence and Cholesky…

Chemical Physics · Physics 2024-06-19 Sophia Burger , Filippo Lipparini , Jürgen Gauss , Stella Stopkowicz

A rigorous analysis is carried out concerning the use of Cholesky decomposition (CD) of two-electron integrals in the case of quantum-chemical calculations with finite or perturbative magnetic fields and gauge-including atomic orbitals. We…

The computation of magnetizability tensors using gauge-including atomic orbitals is discussed in the context of Cholesky decomposition for the two-electron repulsion integrals with a focus on the involved doubly differentiated integrals.…

Chemical Physics · Physics 2024-11-14 Sophia Burger , Stella Stopkowicz , Jürgen Gauss

The development of a novel exact two-component (X2C) scheme with the inclusion of the picture-change correction for the fluctuation potential, the X2Ccorr scheme, is reported, hereby establishing a hierarchy of X2C schemes with systematic…

Chemical Physics · Physics 2026-03-02 Xubo Wang , Sen Wang , Yixuan Wu , Lan Cheng

We report an efficient algorithm using density fitting for the relativistic complete active space self-consistent field (CASSCF) method, which is significantly more stable than the algorithm previously reported by one of the authors [J. E.…

Chemical Physics · Physics 2018-08-01 Ryan D. Reynolds , Takeshi Yanai , Toru Shiozaki

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

We present a polarizable embedding quantum mechanics/molecular mechanics (QM/MM) framework for ground- and excited-state Complete Active Space Self-Consistent Field (CASSCF) calculations on molecules within complex environments, such as…

Chemical Physics · Physics 2024-11-20 Tommaso Nottoli , Mattia Bondanza , Filippo Lipparini , Benedetta Mennucci

We present the time-dependent complete-active-space self-consistent-field (TD-CASSCF) method to simulate multielectron dynamics in ultrafast intense laser fields from the first principles. While based on multiconfiguration expansion, it…

Atomic Physics · Physics 2018-04-24 Takeshi Sato , Yuki Orimo , Takuma Teramura , Oyunbileg Tugs , Kenichi L. Ishikawa

Analytical nuclear gradients for fully internally contracted complete active space second-order perturbation theory (CASPT2) are reported. This implementation has been realized by an automated code generator that can handle spin-free…

Chemical Physics · Physics 2015-02-11 Matthew K. MacLeod , Toru Shiozaki

We compute the Nekrasov partition function of gauge theories on the (resolved) toric singularities C^2/\Gamma in terms of blow-up formulae. We discuss the expansion of the partition function in the \epsilon_1,\epsilon_2 \to 0 limit along…

High Energy Physics - Theory · Physics 2015-06-11 Giulio Bonelli , Kazunobu Maruyoshi , Alessandro Tanzini , Futoshi Yagi

We present the numerical implementation of the time-dependent complete-active-space self-consistent-field (TD-CASSCF) method [Phys. Rev. A, 88, 023402 (2013)] for atoms driven by a strong linearly polarized laser pulse. The present…

An implementation of coupled-cluster (CC) theory to treat atoms and molecules in finite magnetic fields is presented. The main challenges stem from the magnetic-field dependence in the Hamiltonian, or, more precisely, the appearance of the…

Chemical Physics · Physics 2015-09-02 Stella Stopkowicz , Jürgen Gauss , Kai K. Lange , Erik I. Tellgren , Trygve Helgaker

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 describe a method of solving the nuclear Skyrme-Hartree-Fock problem by using a deformed Cartesian harmonic oscillator basis. The complete list of expressions required to calculate local densities, total energy, and self-consistent…

Nuclear Theory · Physics 2009-10-30 J. Dobaczewski , J. Dudek

We present a novel implementation of the complete active space self-consistent field (CASSCF) method that makes use of the many-body expanded full configuration interaction (MBE-FCI) method to incrementally approximate electronic structures…

This review presents a concise, yet comprehensive discussion on the evolution of theoretical methods employed to determine the ground and excited states of molecules in weak and strong magnetic fields. The weak-field cases have been studied…

Atomic and Molecular Clusters · Physics 2021-05-31 Mihir Date , R. W. A Havenith

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

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

We present the one-loop scalar field effective potential for the $N=2$ supersymmetric nonrelativistic self-interacting matter fields coupled to an Abelian Chern-Simons gauge field and for its generalization when bosonic matter fields are…

High Energy Physics - Theory · Physics 2007-05-23 D. Caenepeel , M. Leblanc

Motivated by possible applications to condensed matter systems, in this paper we construct U(N) noncommutative Chern-Simons (NCCS) action for a disc and for a double-layer geometry, respectively. In both cases, gauge invariance severely…

High Energy Physics - Theory · Physics 2009-11-07 Guang-Hong Chen , Yong-Shi Wu
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