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Related papers: Static Embedding with Pair Coupled Cluster Doubles…

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We report a complete implementation of the coupled-cluster method with single, double, and triple excitations (CCSDT) where tensor decompositions are used to reduce its scaling and overall computational costs. For the decomposition of the…

Chemical Physics · Physics 2020-02-20 Michał Lesiuk

We develop a static quantum embedding scheme that utilizes different levels of approximations to coupled cluster (CC) theory for an active fragment region and its environment. To reduce the computational cost, we solve the local fragment…

Chemical Physics · Physics 2024-11-13 Avijit Shee , Fabian M. Faulstich , Birgitta Whaley , Lin Lin , Martin Head-Gordon

In this paper, we scrutinize the ability of seniority-zero wavefunction-based methods to model different types of non-covalent interactions, such as hydrogen bonds, dispersion, and mixed non-covalent interactions as well as prototypical…

Chemical Physics · Physics 2020-02-18 Filip Brzęk , Katharina Boguslawski , Paweł Tecmer , Piotr S. Żuchowski

While restricted single-reference coupled cluster theory truncated to singles and doubles (CCSD) provides very accurate results for weakly correlated systems, it usually fails in the presence of static or strong correlation. This failure is…

Chemical Physics · Physics 2016-02-25 Ireneusz W. Bulik , Thomas M. Henderson , Gustavo E. Scuseria

Unitary coupled cluster (UCC), originally developed as a variational alternative to the popular traditional coupled cluster method, has seen a resurgence as a functional form for use on quantum computers. However, the number of excitors…

Chemical Physics · Physics 2021-01-07 Maria-Andreea Filip , Alex J. W. Thom

We present a novel approach to spin-adapted coupled cluster theory. This approach is based on the entanglement of an open-shell molecule with electrons in a non-interacting bath; together they form a closed-shell state. For the total…

Chemical Physics · Physics 2023-05-22 Sarai Dery Folkestad , Bendik Støa Sannes , Henrik Koch

Multicomponent systems are defined as chemical systems that require a quantum mechanical description of two or more different types of particles. Non-Born-Oppenheimer electron-nuclear interactions in molecules, electron-hole interactions in…

Chemical Physics · Physics 2015-10-21 Benjamin H. Ellis , Somil Aggarwal , Arindam Chakraborty

We present an extension of the pair coupled cluster doubles (p-CCD) method to quasiparticles and apply it to the attractive pairing Hamiltonian. Near the transition point where number symmetry gets spontaneously broken, the proposed…

We describe experimentally observed collective dynamics in colloidal suspensions of model hard-sphere particles using a modified mode coupling theory (MCT). This rescaled MCT is capable to describe quantitatively the wave-vector and…

Soft Condensed Matter · Physics 2024-03-08 Joel Diaz Maier , Joachim Wagner

Doubly occupied configuration interaction (DOCI) with optimized orbitals often accurately describes strong correlations while working in a Hilbert space much smaller than that needed for full configuration interaction. However, the scaling…

Chemical Physics · Physics 2016-02-25 Thomas M. Henderson , Ireneusz W. Bulik , Tamar Stein , Gustavo E. Scuseria

The ground state pairing correlations in finite fermionic systems are described with a high degree of accuracy within a variational approach based on a combined coupled-cluster and particle-number-projected BCS ansatz. The flexibility of…

Nuclear Theory · Physics 2021-06-02 V. V. Baran , J. Dukelsky

The structure of oxide-supported metal nanoclusters plays an essential role in their sharply enhanced catalytic activity over bulk metals. Simulations provide the atomic-scale resolution needed to understand these systems. However, the…

Materials Science · Physics 2024-05-22 Benjamin X. Shi , David J. Wales , Angelos Michaelides , Chang Woo Myung

We combine the electron attachment (EA) and ionization potential (IP) equation-of-motion (EOM) coupled-cluster (CC) approaches with the CC($P$;$Q$) formalism. The resulting methodologies are used to describe the electronic states of several…

Chemical Physics · Physics 2025-09-19 Karthik Gururangan , Stephen H. Yuwono , A. Eugene DePrince , Piotr Piecuch

Adiabatic mixed quantum/classical molecular dynamics simulations were used to generate snapshots of the hydrated electron (e-) in liquid water at 300 K. Water cluster anions that include two complete solvation shells centered on the e- were…

Data Analysis, Statistics and Probability · Physics 2016-09-28 Ilya A. Shkrob , William J. Glover , Ross E. Larsen , Benjamin J. Schwartz

A quantitative description of the excited electronic states of point defects and impurities is crucial for understanding materials properties, and possible applications of defects in quantum technologies. This is a considerable challenge…

Computer simulation is an important tool for scientific progress, especially when lab experiments are either extremely costly and difficult or lack the required resolution. However, all of the simulation methods come with limitations. In…

Fluid Dynamics · Physics 2023-08-04 Edward R. Smith , Panagiotis E. Theodorakis

Quantum computing has emerged as a promising platform for simulating strongly correlated systems in chemistry, for which the standard quantum chemistry methods are either qualitatively inaccurate or too expensive. However, due to the…

Chemical Physics · Physics 2024-05-06 Max Rossmannek , Fabijan Pavošević , Angel Rubio , Ivano Tavernelli

Linear scaling density functional theory approaches to electronic structure are often based on the tendency of electrons to localize even in large atomic and molecular systems. However, in many cases of actual interest, for example in…

Chemical Physics · Physics 2022-03-25 Marcel David Fabian , Ben Shpiro , Roi Baer

Density functional theory (DFT) provides convenient electronic structure methods for the study of molecular systems and materials. Regular Kohn-Sham DFT calculations rely on unitary transformations to determine the ground-state electronic…

Chemical Physics · Physics 2022-10-10 Greta Jacobson , Juan M. Marmolejo-Tejada , Martín A. Mosquera

The double electron attachment (DEA) and double ionization potential (DIP) equation-of-motion coupled-cluster (EOMCC) methods including up to 4-particle-2-hole (4$p$-2$h$) and 4-hole-2-particle (4$h$-2$p$) excitations on top of…

Chemical Physics · Physics 2026-05-21 Jun Shen , Karthik Gururangan , Piotr Piecuch