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We report a new implementation of multireference algebraic diagrammatic construction theory (MR-ADC) for simulations of electron attachment and ionization in strongly correlated molecular systems (EA/IP-MR-ADC). Following our recent work on…

Chemical Physics · Physics 2021-01-19 Koushik Chatterjee , Alexander Yu. Sokolov

We investigate the core-level ionization energies of the bare uranyl ion (UO$_2^{2+}$) and its interaction with X-rays when it is hosted in the Cs$_2$UO$_2$Cl$_4$ crystalline environment using a recent implementation of the…

Chemical Physics · Physics 2024-12-12 Wilken Aldair Misael , Andre Severo Pereira Gomes

Core-polarization interactions are investigated in low-energy electron elastic scattering from the atoms In,Sn,Eu,Au and At through the calculation of their electron affinities. The complex angular momentum method wherein is embedded the…

Atomic Physics · Physics 2015-10-07 Z. Felfli , A. Z. Msezane

The development of relativistic exact two-component (X2C) theory is briefly reviewed, with an emphasis on cost-effective treatments of relativistic two-electron contributions by means of model potential (MP) techniques and closely related…

Chemical Physics · Physics 2025-04-29 Xubo Wang , Chaoqun Zhang , Junzi Liu , Lan Cheng

We present an implementation of equation of motion coupled-cluster singles and doubles (EOM-CCSD) theory using periodic boundary conditions and a plane wave basis set. Our implementation of EOM-CCSD theory is applied to study $F$-centers in…

Materials Science · Physics 2021-02-09 Alejandro Gallo , Felix Hummel , Andreas Irmler , Andreas Grüneis

The magnetic dipole and electric quadrupole hyperfine constants of Aluminium ($^{27}Al$) atom are computed using the relativistic coupled cluster (CC) and unitary coupled cluster (UCC) methods. Effects of electron correlations are…

Atomic Physics · Physics 2007-05-23 Chiranjib Sur , Rajat K. Chaudhuri , B. P. Das , D. Mukherjee

We use the perturbed relativistic coupled-cluster theory to compute the static electric dipole polarizabilities of the singly ionized alkali atoms, namely, Na$^+$, $^+$, Rb$^+$, Cs$^+$ and Fr$^+$. The computations use the…

Atomic Physics · Physics 2013-05-01 S. Chattopadhyay , B. K. Mani , D. Angom

The relativistic coupled-cluster (RCC) method is a powerful many-body method, particularly in the evaluation of electronic wave functions of heavy atoms and molecules, and can be used to calculate various atomic and molecular properties.…

Atomic Physics · Physics 2019-12-09 Nanako Shitara , B. K. Sahoo , T. Watanabe , B. P. Das

In this work we describe the rank-reduced variant of the equation-of-motion coupled cluster theory with complete inclusion of single, double, and triple excitations. The advantage of the proposed formalism in comparison with the canonical…

Chemical Physics · Physics 2026-05-15 Piotr Michalak , Michał Lesiuk

We report the first results of ab initio relativistic correlation calculation of the effective electric field on the electron, E_eff, in the ground state of the HI$^+$ cation. This value is required for interpretation of the suggested…

Atomic Physics · Physics 2013-05-29 T. A. Isaev , N. S. Mosyagin , A. N. Petrov , A. V. Titov

We have implemented noniterative triples corrections to the energy from coupled-cluster with single and double excitations (CCSD) within the 1-electron exact two-component (1eX2C) relativistic framework. The effectiveness of both the…

We present the theory and the implementation of a low-cost four-component relativistic equation of motion coupled cluster method for ionized states based on frozen natural spinors. A single threshold (natural spinor occupancy) can control…

Chemical Physics · Physics 2024-06-19 Kshitijkumar Surjuse , Somesh Chamoli , Malaya K. Nayak , Achintya Kumar Dutta

A relativistic coupled-cluster (RCC) theory is implemented to study electron impact excitations of atomic species. As a test case, the electron impact excitations of the $3s ~ ^2S_{1/2} - 3p ~ ^2P_{1/2;3/2}$ resonance transitions are…

Atomic Physics · Physics 2018-02-14 L. Sharma , B. K. Sahoo , P. Malkar , R. Srivastava

An approximate relativistic two-component Hamiltonian for use in molecular electronic structure calculations is derived in the form of a sum of fixed atom-centered kinetic and spin-orbit operators added to the non-relativistic Hamiltonian.…

Chemical Physics · Physics 2019-02-13 Dimitri N. Laikov

The successive ionization potentials (IPs) and electron affinities (EAs) for superheavy elements with $111 \leq Z \leq 114$, namely, Rg, Cn, Nh, and Fl are reexamined using the relativistic Fock-space coupled-cluster method with…

We present the implementation of quadratic response theory based upon the relativistic equation-of-motion coupled cluster method. We showcase our implementation, whose generality allows us to consider both time-dependent and…

Chemical Physics · Physics 2024-01-29 Xiang Yuan , Loic Halbert , Lucas Visscher , Andre Severo Pereira Gomes

The relativistic coupled-cluster single-double method is used to calculate the dependence of frequencies of strong $E1$-transitions in many monovalent atoms and ions on the fine-structure constant $\alpha$. These transitions are used in the…

Atomic Physics · Physics 2009-11-13 V. A. Dzuba , W. R. Johnson

We have developed a reduced-cost non-Dyson third-order algebraic diagrammatic construction theory for the electron-attachment problem based on state-specific frozen natural orbitals. Density fitting and truncated natural auxiliary functions…

Chemical Physics · Physics 2026-03-13 Tamoghna Mukhopadhyay , Kamal Majee , Achintya Kumar Dutta

We have developed a relativistic coupled-cluster theory to incorporate nuclear spin-dependent interaction Hamiltonians perturbatively. In this theory, the coupled-cluster operators in the electronic sector are defined as tensor operators of…

Atomic Physics · Physics 2011-05-19 B. K. Mani , D. Angom

In this article, the molecular permanent electric dipole moments and components of static dipole polarizabilities for the electronic ground state of singly charged aluminum monohalides are reported. The coupled-cluster method by considering…

Atomic Physics · Physics 2024-06-18 Ankush Thakur , Renu Bala , H. S. Nataraj , V. S. Prasannaa