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Related papers: State-Specific Configuration Interaction for Excit…

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The accurate description of doubly-excited states using conventional electronic structure methods is remarkably challenging, primarily because such excited states require the inclusion of doubly or higher excited configurations or the…

Chemical Physics · Physics 2019-05-01 Katharina Boguslawski

In this study, we extend the multicomponent heat-bath configuration interaction (HCI) method to excited states. Previous multicomponent HCI studies have been performed using only the variational stage of the HCI algorithm as they have…

Chemical Physics · Physics 2022-01-12 Naresh Alaal , Kurt R. Brorsen

We present a stable and systematically improvable quantum Monte Carlo (QMC) approach to calculating excited-state energies, which we implement using our fast randomized iteration method for the full configuration interaction problem…

Computational Physics · Physics 2023-10-03 Samuel M. Greene , Robert J. Webber , James E. T. Smith , Jonathan Weare , Timothy C. Berkelbach

Quantum-selected configuration interaction (QSCI) is a novel quantum-classical hybrid algorithm for quantum chemistry calculations. This method identifies electron configurations having large weights for the target state using quantum…

Chemical Physics · Physics 2025-03-31 Soichi Shirai , Shih-Yen Tseng , Hokuto Iwakiri , Takahiro Horiba , Hirotoshi Hirai , Sho Koh

The perturbatively selected configuration interaction scheme (CIPSI) is particularly effective in constructing determinantal expansions for quantum Monte Carlo (QMC) simulations with Jastrow-Slater wave functions: fast and smooth…

Classical Physics · Physics 2021-03-02 Monika Dash , Saverio Moroni , Claudia Filippi , Anthony Scemama

Excited states exhibiting double excitation character are notoriously difficult to model using conventional single-reference methods, such as adiabatic time-dependent density-functional theory (TD-DFT) or equation-of-motion coupled cluster…

We combine recent advances in excited state variational principles, fast multi-Slater Jastrow methods, and selective configuration interaction to create multi-Slater Jastrow wave function approximations that are optimized for individual…

Strongly Correlated Electrons · Physics 2019-06-19 Sergio D. Pineda Flores , Eric Neuscamman

By combining extrapolated selected configuration interaction (sCI) energies obtained with the CIPSI (Configuration Interaction using a Perturbative Selection made Iteratively) algorithm with the recently proposed short-range…

Chemical Physics · Physics 2020-06-05 Emmanuel Giner , Anthony Scemama , Julien Toulouse , Pierre-François Loos

Methods for correcting residual energy errors of configuration interaction (CI) calculations of molecules and other electronic systems are discussed based on the assumption that the energy defect can be mapped onto atomic regions. The…

Chemical Physics · Physics 2022-10-05 Jerry L. Whitten

The development of variational density functional theory approaches to excited electronic states is impeded by limitations of the commonly used self-consistent field (SCF) procedure. A method based on a direct optimization approach as well…

Chemical Physics · Physics 2022-11-09 Gianluca Levi , Aleksei V. Ivanov , Hannes Jónsson

Selected configuration interaction (SCI) methods have emerged as state-of-the-art methodologies for achieving high accuracy and generating benchmark reference data for ground and excited states in small molecular systems. However, their…

Chemical Physics · Physics 2024-06-13 Hugh G. A. Burton , Pierre-François Loos

We study several approaches to orbital optimization in selected configuration interaction plus perturbation theory (SCI+PT) methods, and test them on the ground and excited states of three molecules using the semistochastic heatbath…

Chemical Physics · Physics 2021-07-14 Yuan Yao , C. J. Umrigar

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

The total energies of twenty eight bound S-, P-, D-, F-, G-, H-, and I-states in the three-electron systems Li atom and Be+ ion, respectively, are determined with the use of the Configuration Interaction (CI) with Slater orbitals and L-S…

Atomic Physics · Physics 2013-08-09 Maria Belen Ruiz , Johannes T. Margraf , Alexei M. Frolov

We propose quantum-selected configuration interaction (QSCI), a class of hybrid quantum-classical algorithms for calculating the ground- and excited-state energies of many-electron Hamiltonians on noisy quantum devices. Suppose that an…

Quantum Physics · Physics 2023-02-23 Keita Kanno , Masaya Kohda , Ryosuke Imai , Sho Koh , Kosuke Mitarai , Wataru Mizukami , Yuya O. Nakagawa

Numerous numerical studies have shown that geminal-based methods are a promising direction to model strongly correlated systems with low computational costs. Several strategies have been introduced to capture the missing dynamical…

Chemical Physics · Physics 2023-03-22 Artur Nowak , Katharina Boguslawski

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

Inspired by our earlier semi-stochastic work aimed at converging high-level coupled-cluster (CC) energetics [J. E. Deustua, J. Shen, and P. Piecuch, Phys. Rev. Lett. 119, 223003 (2017); J. Chem. Phys. 154, 124103 (2021)], we propose a novel…

Chemical Physics · Physics 2022-10-06 Karthik Gururangan , J. Emiliano Deustua , Jun Shen , Piotr Piecuch

We develop a cubic scaling approach to excited-state-specific second order perturbation theory in which the completeness of a local correlation treatment is carefully matched between the ground and excited state. With this matching, the…

Chemical Physics · Physics 2025-05-14 Rachel Clune , Eric Neuscamman

We present a first principles strategy for developing state-specific density functional approximations for excited states. We first clarify why approaches based on conventional ground state approximations miss density-driven correlations,…

Chemical Physics · Physics 2025-06-09 Tim Gould , Stephen G Dale , Leeor Kronik , Stefano Pittalis