Improvement of the coupled-cluster singles and doubles method via scaling same- and opposite-spin components of the double excitation correlation energy

2008 ◽  
Vol 128 (12) ◽  
pp. 124111 ◽  
Author(s):  
Tait Takatani ◽  
Edward G. Hohenstein ◽  
C. David Sherrill
Keyword(s):  
Correlation Energy ◽  
Coupled Cluster ◽  
Double Excitation

Linear scaling coupled cluster method with correlation energy based error control

2010 ◽  
Vol 133 (1) ◽  
pp. 014107 ◽  
Author(s):  
Marcin Ziółkowski ◽  
Branislav Jansík ◽  
Thomas Kjærgaard ◽  
Poul Jørgensen
Keyword(s):  
Error Control ◽  
Correlation Energy ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Linear Scaling ◽  
Coupled Cluster Method

Analytic evaluation of energy gradients for the single and double excitation coupled cluster (CCSD) wave function: Theory and application

1987 ◽  
Vol 87 (9) ◽  
pp. 5361-5373 ◽  
Author(s):  
Andrew C. Scheiner ◽  
Gustavo E. Scuseria ◽  
Julia E. Rice ◽  
Timothy J. Lee ◽  
Henry F. Schaefer
Keyword(s):  
Wave Function ◽  
Function Theory ◽  
Coupled Cluster ◽  
Double Excitation ◽  
Analytic Evaluation

A systematic theoretical study of harmonic vibrational frequencies: The single and double excitation coupled cluster (CCSD) method

1988 ◽  
Vol 89 (1) ◽  
pp. 360-366 ◽  
Author(s):  
Brent H. Besler ◽  
Gustavo E. Scuseria ◽  
Andrew C. Scheiner ◽  
Henry F. Schaefer
Keyword(s):  
Theoretical Study ◽  
Vibrational Frequencies ◽  
Coupled Cluster ◽  
Double Excitation ◽  
Ccsd Method

Towards density functional approximations from coupled cluster correlation energy densities

2019 ◽  
Vol 150 (24) ◽  
pp. 244116 ◽  
Author(s):  
Johannes T. Margraf ◽  
Christian Kunkel ◽  
Karsten Reuter
Keyword(s):  
Density Functional ◽  
Correlation Energy ◽  
Coupled Cluster ◽  
Cluster Correlation

Dynamical Electron Correlation Within Hartree-Fock Limitation

2017 ◽  
Author(s):  
Arijit Bag
Keyword(s):  
Small Molecules ◽  
Electron Correlation ◽  
Present Method ◽  
Correlation Energy ◽  
Electronic Structure Theory ◽  
Structure Theory ◽  
Coupled Cluster ◽  
Energy Correlation ◽  
Good Tool ◽  
Hartree Fock

<b>Aim:</b> Calculation of dynamical electron<br>correlation energy within Hartree Fock formalism<br>to achieve post Hartree Fock accuracy.<br><br><b>Achievement: </b>Using intermediate Hamiltonian<br>technique and perturbation methodology we can<br>construct a weave equation which on projection<br>gives very simple equation for correlation<br>energy. Correlation energy only depends on the<br>amount of perturbation. This method is applied<br>for few small molecules. It is found that this<br>method produces very accurate results which is<br>comparable to CCSD method.<br><br><b>Conclusion:</b> The present method which is<br>termed as Extended Hartree Fock (EHF)<br>method is proved to be a very good tool for<br>electronic structure theory as its computational<br>requirement is equivalent to HF method but its<br>accuracy is comparable to Coupled Cluster<br>based methods.<br><br>

Dynamical Electron Correlation Within Hartree-Fock Limitation

2017 ◽  
Author(s):  
Arijit Bag
Keyword(s):  
Small Molecules ◽  
Electron Correlation ◽  
Present Method ◽  
Correlation Energy ◽  
Electronic Structure Theory ◽  
Structure Theory ◽  
Coupled Cluster ◽  
Energy Correlation ◽  
Good Tool ◽  
Hartree Fock

<b>Aim:</b> Calculation of dynamical electron<br>correlation energy within Hartree Fock formalism<br>to achieve post Hartree Fock accuracy.<br><br><b>Achievement: </b>Using intermediate Hamiltonian<br>technique and perturbation methodology we can<br>construct a weave equation which on projection<br>gives very simple equation for correlation<br>energy. Correlation energy only depends on the<br>amount of perturbation. This method is applied<br>for few small molecules. It is found that this<br>method produces very accurate results which is<br>comparable to CCSD method.<br><br><b>Conclusion:</b> The present method which is<br>termed as Extended Hartree Fock (EHF)<br>method is proved to be a very good tool for<br>electronic structure theory as its computational<br>requirement is equivalent to HF method but its<br>accuracy is comparable to Coupled Cluster<br>based methods.<br><br>

C2V Insertion pathway for BeH2: A test problem for the coupled-cluster single and double excitation model

1983 ◽  
Vol 23 (3) ◽  
pp. 835-845 ◽  
Author(s):  
George D. Purvis ◽  
Ron Shepard ◽  
Franklin B. Brown ◽  
Rodney J. Bartlett
Keyword(s):  
Test Problem ◽  
Coupled Cluster ◽  
Double Excitation ◽  
Excitation Model
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