The description of N2 and F2 potential energy surfaces using multireference coupled cluster theory

1987 ◽  
Vol 86 (2) ◽  
pp. 887-907 ◽  
Author(s):  
William D. Laidig ◽  
Paul Saxe ◽  
Rodney J. Bartlett
Keyword(s):  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Coupled Cluster ◽  
Coupled Cluster Theory ◽  
Cluster Theory ◽  
Energy Surfaces

Frozen Natural Orbitals: Systematic Basis Set Truncation for Coupled-Cluster Theory

2005 ◽  
Vol 70 (6) ◽  
pp. 837-850 ◽  
Author(s):  
Andrew G. Taube ◽  
Rodney J. Bartlett
Keyword(s):  
Small Molecules ◽  
Potential Energy Surfaces ◽  
Equilibrium Structure ◽  
Virtual Space ◽  
Basis Set ◽  
Coupled Cluster ◽  
Coupled Cluster Theory ◽  
Cluster Theory ◽  
Equilibrium Structures ◽  
Energy Surfaces

The method of frozen natural orbital (FNO) basis set truncation for coupled-cluster theory is described. Numerical comparisons of the FNO potential energy surfaces of a group of small molecules at the CCSD(T) level in DZP, cc-pVTZ, cc-pVQZ bases show that truncation of up to 50% of the virtual space yields CC correlation energies that are accurate to 90 or 95% when added to the full MBPT(2) basis result. The FNO truncation method is also applied to dimethylnitramine (DMNA): both the equilibrium structure and dimer interactions, yielding results at the CCSD(T) level in both a DZP and cc-pVTZ basis set that agree with literature values. CCSD(T) calculations at two possible equilibrium structures of 1,3,5-trinitrohexahydro-1,3,5-triazine (RDX) in a truncated DZP basis are also reported.

Accuracy of Coupled Cluster Excited State Potential Energy Surfaces

2018 ◽  
Vol 14 (11) ◽  
pp. 5859-5869 ◽  
Author(s):  
Attila Tajti ◽  
John F. Stanton ◽  
Devin A. Matthews ◽  
Péter G. Szalay
Keyword(s):  
Excited State ◽  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Coupled Cluster ◽  
State Potential ◽  
Energy Surfaces

scholarly journals van der Waals potential energy surfaces from the exchange-hole dipole moment dispersion model

2016 ◽  
Vol 94 (12) ◽  
pp. 1049-1056 ◽  
Author(s):  
Joseph B. Dizon ◽  
Erin R. Johnson
Keyword(s):  
Dipole Moment ◽  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Reference Data ◽  
Dispersion Model ◽  
Binding Energies ◽  
Coupled Cluster ◽  
Global Minima ◽  
Hybrid Functional ◽  
Energy Surfaces

The potential energy surfaces (PESs) of 28 simple van der Waals complexes, each consisting of a rare-gas (Rg) atom interacting with a linear molecule, are calculated using the exchange-hole dipole moment (XDM) dispersion model in conjunction with three base density functionals (HFPBE, PW86PBE, and a commensurate hybrid functional). Results are compared with literature coupled-cluster reference data. The quality of the computed PESs is assessed based on the positions of the global minima and the corresponding binding energies. Only the hybrid functional is found to provide generally reliable PESs. Dispersion-corrected HFPBE strongly underestimates the equilibrium intermolecular separations and predicts different global minima than the reference PESs for Rg–HCl, Rg–HBr, and two of the Rg–HCN complexes. Analysis of the binding-energy errors reveals that the performance of HFPBE degrades as the size of the Rg atoms increase down the group, while the performance of PW86PBE is significantly worse for strongly-polar molecules. PW86PBE, and to a lesser extent the hybrid, strongly overbind Kr–HF due to charge-transfer error. Despite this, the XDM-corrected hybrid functional displays the best overall error statistics and provides binding energies to within ca. 10 cm–1 of the coupled-cluster reference data at a greatly reduced computational cost.

Sign in / Sign up

Export Citation Format

Share Document