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Related papers: Time-dependent multiconfiguration self-consistent-…

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Multi-configuration range-separated density-functional theory is extended to the time-dependent regime. An exact variational formulation is derived. The approximation, which consists in combining a long-range…

Chemical Physics · Physics 2013-02-27 Emmanuel Fromager , Stefan Knecht , Hans Jørgen Aa. Jensen

The time-dependent equation-of-motion coupled cluster (TD-EOM-CC) and time-dependent coupled cluster (TDCC) methods are compared by simulating Rabi oscillations for different numbers of non-interacting atoms in a classical electromagnetic…

Chemical Physics · Physics 2023-10-02 Andreas S. Skeidsvoll , Henrik Koch

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

We investigate the numerical stability of time-dependent coupled-cluster theory for many-electron dynamics in intense laser pulses, comparing two coupled-cluster formulations with full configuration interaction theory. Our numerical…

We present a computationally efficient approach to solve the time-dependent Kohn-Sham equations in real-time using higher-order finite-element spatial discretization, applicable to both pseudopotential and all-electron calculations. To this…

Computational Physics · Physics 2019-10-02 Bikash Kanungo , Vikram Gavini

The time-dependent density functional theory (TDDFT) has been broadly used to investigate the excited-state properties of various molecular systems. However, the current TDDFT heavily relies on outcomes from the corresponding ground-state…

Chemical Physics · Physics 2020-09-02 Shu-Hao Yeh , Aaditya Manjanath , Yuan-Chung Cheng , Jeng-Da Chai , Chao-Ping Hsu

The multi-configurational self-consistent field theory is considered the standard starting point for almost all multireference approaches required for strongly-correlated molecular problems. The limitation of the approach is generally given…

Chemical Physics · Physics 2015-10-14 Robert E. Thomas , Qiming Sun , Ali Alavi , George H. Booth

The performance of time-independent, orbital optimized calculations of excited states is assessed with respect to charge transfer excitations in organic molecules in comparison to the linear-response time-dependent density functional theory…

Chemical Physics · Physics 2024-05-22 Elli Selenius , Alec Elías Sigurdarson , Yorick L. A. Schmerwitz , Gianluca Levi

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

This chapter provides a basic introduction to excited-state extensions of density functional theory (DFT), including time-dependent (TD-)DFT in both its linear-response and its explicitly time-dependent formulations. As applied to the…

Chemical Physics · Physics 2023-05-02 John M. Herbert

We discuss the multispecies time-dependent restricted-active-space self-consistent-field theory, an \textit{ab initio} wavefunction-based theory for mixtures of ultracold atomic and molecular gases. We present the general theory, based on…

Quantum Physics · Physics 2018-08-01 Camille Lévêque , Lars Bojer Madsen

The structure of approximate two electron wavefunction is deeply investigated, both theoretically and numerically, in the strong-field driven ionization dynamics. Theoretical analyses clarify that for two electron singlet systems, the…

Atomic Physics · Physics 2014-11-13 Takeshi Sato , Kenichi L Ishikawa

We extend the localized operator partitioning method (LOPM) [J. Nagesh, A.F. Izmaylov, and P. Brumer, J. Chem. Phys. 142, 084114 (2015)] to the time-dependent density functional theory (TD-DFT) framework to partition molecular electronic…

Chemical Physics · Physics 2017-09-13 Jayashree Nagesh , Michael J. Frisch , Paul Brumer , Artur F. Izmaylov

A configuration-interaction time-dependent density functional theory (CI-TDDFT) for nuclear dynamics is developed. In this framework, the correlated nuclear many-body wave function is expanded in terms of time-dependent many-particle…

Nuclear Theory · Physics 2026-05-21 Y. P. Wang , B. Li , D. Vretenar , T. Nikšić , P. W. Zhao , J. Meng

In contrast to the original Kohn-Sham (KS) formalism, we propose a density functional theory (DFT) with fractional orbital occupations for the study of ground states of many-electron systems, wherein strong static correlation is shown to be…

Chemical Physics · Physics 2015-06-03 Jeng-Da Chai

In this work we present a multi-orbital form of the Two-Particle Self-Consistent approach (TPSC), here the effective local and static irreducible interaction vertices are determined by means of the Dynamical Mean-Field Theory (DMFT). This…

Strongly Correlated Electrons · Physics 2023-06-16 Karim Zantout , Steffen Backes , Aleksandar Razpopov , Dominik Lessnich , Roser Valenti

We present an efficient orbital optimization procedure that combines the highly GPU accelerated, spin-adapted density matrix renormalization group (DMRG) method with the complete active space self-consistent field (CAS-SCF) approach for…

The time-dependent Schr\"odinger equation (TDSE) in real space is fundamental to understanding the dynamics of many-electron quantum systems, with applications ranging from quantum chemistry to condensed matter physics and materials…

Quantum Physics · Physics 2026-03-31 Enze Hou , Yuzhi Liu , Linxuan Zhang , Difa Ye , Lei Wang , Han Wang

We present a real-space formulation and higher-order finite-difference implementation of periodic Orbital-free Density Functional Theory (OF-DFT). Specifically, utilizing a local reformulation of the electrostatic and kernel terms, we…

Computational Physics · Physics 2015-12-23 Swarnava Ghosh , Phanish Suryanarayana

A direct orbital optimization method is presented for density functional calculations of excited electronic states using either a real space grid or a plane wave basis set. The method is variational, provides atomic forces in the excited…

Computational Physics · Physics 2022-11-09 Aleksei V. Ivanov , Gianluca Levi , Elvar Ö. Jónsson , Hannes Jónsson