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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

In this paper, we report on the implementation of the EOM spin-flip (SF), ionization-potential (IP) and electron-affinity (EA) coupled cluster singles doubles (CCSD) methods for atoms and molecules in strong magnetic fields for energies as…

Chemical Physics · Physics 2025-10-08 Marios-Petros Kitsaras , Florian Hampe , Lena Reimund , Stella Stopkowicz

We recently proposed a novel approach to converging electronic energies equivalent to high-level coupled-cluster (CC) computations by combining the deterministic CC($P$;$Q$) formalism with the stochastic configuration interaction (CI) and…

Chemical Physics · Physics 2021-03-23 J. Emiliano Deustua , Jun Shen , Piotr Piecuch

We propose and develop the complex scaled multiconfigurational spin-tensor electron propagator (CMCSTEP) technique for theoretical determination of resonance parameters with electron-atom/molecule systems including open-shell and highly…

Atomic Physics · Physics 2015-06-23 Tsogbayar Tsednee , Liyuan Liang , Danny L. Yeager

We have performed systematic large-scale all-electron correlated calculations on boron Bn, aluminum Aln and magnesium Mgn clusters (n=2--5), to study their linear optical absorption spectra. Several possible isomers of each cluster were…

Atomic and Molecular Clusters · Physics 2016-07-26 Ravindra Shinde

We present a computationally efficient relativistic formulation of the equation-of-motion coupled-cluster method for the double electron attachment problem. In this work, the exact two-component Hamiltonian within the atomic mean-field…

Chemical Physics · Physics 2026-03-31 Sujan Mandal , Tamoghna Mukhopadhyay , Achintya Kumar Dutta

Regge-pole calculated low-energy electron elastic total cross sections (TCSs) for complex heavy atoms and fullerene molecules are characterized generally by ground, metastable, and excited negative-ion formation, shape resonances and…

Atomic and Molecular Clusters · Physics 2021-11-09 Zineb Felfli , Alfred Z. Msezane

In the molecular quantum chemistry community, coupled-cluster (CC) methods are well-recognized for their systematic convergence and reliability. The extension of the theory to extended systems has been comparably recent, so that…

Chemical Physics · Physics 2024-10-31 Andreas Grüneis , Evgeny Moerman , Matthias Scheffler , Tonghao Shen , Igor Ying Zhang

Roles of electron correlation effects in the determination of attachment energies, magnetic dipole hyperfine structure constants and electric dipole (E1) matrix elements of the low-lying states in the singly charged cadmium ion (Cd$^+$)…

Atomic Physics · Physics 2018-03-14 Cheng-Bin Li , Yan-Mei Yu , B. K. Sahoo

The cluster expansion method is applied to electronic excitations and a set of effective cluster density of states (ECDOS) are defined, analogous to effective cluster interactions (ECI). The ECDOS are used to generate alloy thermodynamic…

Materials Science · Physics 2012-03-06 H. Y. Geng , M. H. F. Sluiter , N. X. Chen

We introduce a novel class of coupled cluster (CC) methods that leverage the seniority concept to enhance efficiency and accuracy in electronic structure calculations. While existing approaches, such as the pair coupled cluster doubles…

The Regge-pole calculated low-energy electron elastic total cross sections (TCSs) for Cm and No, characterized generally by negative-ion formation, shape resonances and Ramsauer-Townsend(R-T) minima, exhibit atomic and fullerene molecular…

Atomic Physics · Physics 2019-10-01 Alfred Z. Msezane , Zineb Felfli

Relativistic close coupling calculations are reported for unified electronic recombination of (e + C IV) including non-resonant and resonant recombination processes, radiative and dielectronic recombination (RR and DR). Detailed comparison…

Astrophysics · Physics 2008-11-26 Anil K. Pradhan , Guo Xin Chen , Sultana N. Nahar , Hong Lin Zhang

Unitary Coupled Cluster (UCC) theory is a promising variational method for electronic structure calculations, especially for strongly correlated systems and quantum computers. However, its practical application is limited by the steep…

Chemical Physics · Physics 2026-02-05 Prateek Vaish , Brenda Rubenstein

Resonances from electron attachment to $\text{NO}_2$ have been identified in the total electron scattering cross sections (TCS) measured with a magnetically confined electron transmission apparatus. The corresponding absolute electron…

Chemical Physics · Physics 2026-05-29 Ana I. Lozano , Francisco Blanco , Juan C. Oller , Paulo Limão-Vieira , Gustavo García

Recent years have seen the development of two types of non-local extensions to the single-site dynamical mean field theory. On one hand, cluster approximations, such as the dynamical cluster approximation, recover short-range…

Strongly Correlated Electrons · Physics 2018-03-21 Sergei Iskakov , Hanna Terletska , Emanuel Gull

Quantum chemical methods dealing with challenging systems while retaining low computational costs have attracted attention. In particular, many efforts have been devoted to developing new methods based on the second-order perturbation that…

Chemical Physics · Physics 2023-10-30 Nhan Tri Tran , Hoang Thanh Nguyen , Lan Nguyen Tran

We present the first application to real molecular systems of the recently proposed linear-response theory for the density-based basis-set correction method [J. Chem. Phys. 158, 234107 (2023)]. We apply this approach to accelerate the…

Chemical Physics · Physics 2024-02-27 Diata Traore , Julien Toulouse , Emmanuel Giner

We scrutinize the performance of different variants of equation of motion coupled cluster (EOM-CC) methods to predict electronic excitation energies and excited state potential energy surfaces in closed-shell actinide species. We focus our…

Chemical Physics · Physics 2020-02-26 Artur Nowak , Paweł Tecmer , Katharina Boguslawski

Energy spectra and angular distributions have been measured of electrons that are emitted upon disassembly of $Xe_{150000}$ following irradiation by intense (10$^{15}-10^{16}$ W cm$^{-2}$) laser pulses whose durations are varied over the…

Atomic and Molecular Clusters · Physics 2009-11-07 V. Kumarappan , M. Krishnamurthy , D. Mathur