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Multiconfiguration pair-density functional theory (MC-PDFT) is a post-MCSCF multireference electronic-structure method that explicitly models strong electron correlation, and linearized pair-density functional theory (L-PDFT) is a recently…

Analytic gradient routines are a desirable feature for quantum mechanical methods, allowing for efficient determination of equilibrium and transition state structures and several other molecular properties. In this work, we present…

Nonadiabatic molecular dynamics is an effective method for modeling nonradiative decay in electronically excited molecules. Its accuracy depends strongly on the quality of the potential energy surfaces, and its affordability for long…

Chemical Physics · Physics 2024-10-11 Matthew R. Hennefarth , Donald G. Truhlar , Laura Gagliardi

Multiconfiguration pair-density functional theory (MC-PFDT) has previously been applied successfully to carry out ground-state and excited-state calculations. However, because it includes no interaction between electronic states, MC-PDFT…

This work presents the formalism and implementation of excited state nuclear forces within density functional linear response theory (TDDFT) using a plane wave basis set. An implicit differentiation technique is developed for computing…

Other Condensed Matter · Physics 2009-11-11 Nikos L. Doltsinis , D. S. Kosov

The computational investigation of photochemical processes often entails the calculation of excited state geometries, energies, and energy gradients. The nuclear-electronic orbital (NEO) approach treats specified nuclei, typically protons,…

The multiscale model combining the multiconfigurational self-consistent field (MCSCF) method with the fully atomistic polarizable Fluctuating Charges (FQ) force field (J. Chem. Theory Comput. 2024, 20, 9954-9967) is here extended to the…

Chemical Physics · Physics 2025-11-14 Francesco Mazza , Marco Trinari , Chiara Sepali , Chiara Cappelli

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

In this paper, we study the nuclear gradients of heat bath configuration interaction self-consistent field (HCISCF) wave functions and use them to optimize molecular geometries for various molecules. We show that the HCISCF nuclear…

Chemical Physics · Physics 2022-09-14 James E. T. Smith , Joonho Lee , Sandeep Sharma

A global hybrid extension of variational two-electron reduced-density matrix (v2RDM)-driven multiconfiguration pair-density functional theory (MCPDFT) is developed. Using a linear decomposition of the electron-electron repulsion term, a…

Chemical Physics · Physics 2019-11-27 Mohammad Mostafanejad , Marcus Dante Liebenthal , A. Eugene DePrince

Due to their small size and unique properties, single-molecule electronics have long seen research interest from experimentalists and theoreticians alike. From a theoretical standpoint, modeling these systems using electronic structure…

Chemical Physics · Physics 2021-10-04 Andrew M. Sand , Justin T. Malme , Erik P. Hoy

Molecular dynamics (MD) simulation, which is considered an important tool for studying physical and chemical processes at the atomic scale, requires accurate calculations of energies and forces. Although reliable energies and forces can be…

Materials Science · Physics 2021-12-06 Van-Quyen Nguyen , Viet-Cuong Nguyen , Tien-Cuong Nguyen , Tien-Lam Pham

Complete active space self-consistent field (CASSCF) computations can be realized at polynomial cost via the variational optimization of the active-space two-electron reduced-density matrix (2-RDM). Like conventional approaches to CASSCF,…

Chemical Physics · Physics 2018-12-10 Mohammad Mostafanejad , A. Eugene DePrince

The ground-state properties of superfluid nuclear systems with ^1S_0 pairing are studied within a local energy-density functional (LEDF) approach. A new form of the LEDF is proposed with a volume part which fits the Friedman- Pandharipande…

Nuclear Theory · Physics 2011-04-15 S. A. Fayans , D. Zawischa

Covariant density functional theory (CDFT) is a modern theoretical tool for the description of nuclear structure phenomena. The current investigation aims at the global assessment of the accuracy of the description of the ground state…

Nuclear Theory · Physics 2015-06-19 S. E. Agbemava , A. V. Afanasjev , D. Ray , P. Ring

A new method to calculate spectroscopic properties of deformed nuclei is proposed: configuration interaction on top of projected density functional theory (CI-PDFT). The general concept of this approach is discussed in the framework of…

Nuclear Theory · Physics 2016-10-12 P. W. Zhao , P. Ring , J. Meng

State-specific orbital optimized approaches are more accurate at predicting core-level spectra than traditional linear-response protocols, but their utility had been restricted on account of the risk of `variational collapse' down to the…

Density functional theory (DFT) became a universal approach to compute ground-state and excited configurations of many-electron systems held together by an external one-body potential in condensed-matter, atomic, and molecular physics. At…

Nuclear Theory · Physics 2011-09-30 J. Dobaczewski

Superfluidity is a generic feature of various quantum systems at low temperatures and it is in particular important for the description of dynamics of low energy nuclear reactions. The time-dependent density functional theory (TDDFT) is, to…

Nuclear Theory · Physics 2020-07-15 M. C. Barton , S. Jin , P. Magierski , K. Sekizawa , G. Wlazłowski , A. Bulgac

Exascale computing could soon enable a predictive theory of nuclear structure and reactions rooted in the Standard Model, with quantifiable and systematically improvable uncertainties. Such a predictive theory will help exploit experiments…

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