Spin polynomial similarity transformation for repulsive Hamiltonians: interpolating between coupled cluster and spin-projected unrestricted Hartree–Fock

2017 ◽  
Vol 19 (33) ◽  
pp. 22385-22394 ◽  
Author(s):  
John A. Gomez ◽  
Matthias Degroote ◽  
Jinmo Zhao ◽  
Yiheng Qiu ◽  
Gustavo E. Scuseria
Keyword(s):  
Strong Correlation ◽  
Similarity Transformation ◽  
Coupled Cluster ◽  
Hartree Fock

Our overarching goal is to be able to describe both weak and strong correlation with a single, computationally affordable method without sacrificing important qualities of the wavefunction, e.g. symmetries of the Hamiltonian.

Coupled-cluster method in Fock space. II. Brueckner-Hartree-Fock method

1985 ◽  
Vol 32 (2) ◽  
pp. 743-747 ◽  
Author(s):  
Leszek Z. Stolarczyk ◽  
Hendrik J. Monkhorst
Keyword(s):  
Fock Space ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Coupled Cluster Method ◽  
Hartree Fock

Analytic energy gradients for open-shell coupled-cluster singles and doubles (CCSD) calculations using restricted open-shell Hartree—Fock (ROHF) reference functions

1991 ◽  
Vol 182 (3-4) ◽  
pp. 207-215 ◽  
Author(s):  
Jürgen Gauss ◽  
Walter J. Lauderdale ◽  
John F. Stanton ◽  
John D. Watts ◽  
Rodney J. Bartlett
Keyword(s):  
Open Shell ◽  
Coupled Cluster ◽  
Hartree Fock ◽  
Reference Functions

Spin adapted restricted Hartree–Fock reference coupled cluster theory for open shell systems

1994 ◽  
Vol 100 (5) ◽  
pp. 3706-3716 ◽  
Author(s):  
Pavel Neogrády ◽  
Miroslav Urban ◽  
Ivan Hubac̆
Keyword(s):  
Open Shell ◽  
Coupled Cluster ◽  
Coupled Cluster Theory ◽  
Cluster Theory ◽  
Hartree Fock

scholarly journals Describing Strong Correlation with Block-Correlated Coupled Cluster Theory

2020 ◽  
Vol 11 (18) ◽  
pp. 7536-7543
Author(s):  
Qingchun Wang ◽  
Mingzhou Duan ◽  
Enhua Xu ◽  
Jingxiang Zou ◽  
Shuhua Li
Keyword(s):  
Strong Correlation ◽  
Coupled Cluster ◽  
Coupled Cluster Theory ◽  
Cluster Theory

Perturbation theory of short-range atomic interactions

1970 ◽  
Vol 317 (1531) ◽  
pp. 545-574 ◽  
Keyword(s):  
Perturbation Theory ◽  
Short Range ◽  
Similarity Transformation ◽  
Order Theory ◽  
First Order ◽  
Hartree Fock ◽  
First Order Theory ◽  
Atomic Interactions ◽  
Cusp Conditions ◽  
Molecular Calculations

A new united atom perturbation theory of the interaction of two atoms at small separations is described. The key feature is a similarity transformation of the Schrödinger equation which enables the cusp conditions to be satisfied at both nuclei and preserves the correct molecular symmetry. The first-order theory is examined in detail and compared with other united atom theories. Numerical calculations are presented for the ground states of the systems H + 2 , HeH 2+ HeH, He 2 and Li + He, based mainly on Hartree-Fock wavefunctions for the united atoms, and are compared with accurate molecular calculations. The agreement is remarkably good for separations up to 1 bohr.

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