The equation-of-motion coupled-cluster method: Excitation energies of Be and CO

1989 ◽  
Vol 164 (1) ◽  
pp. 57-62 ◽  
Author(s):  
Jan Geertsen ◽  
Magnus Rittby ◽  
Rodney J. Bartlett
Keyword(s):  
Equation Of Motion ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Coupled Cluster Method ◽  
Excitation Energies

A Multi-Layer Approach to the Equation of Motion Coupled-Cluster Method for the Electron Affinity

2020 ◽  
Author(s):  
Soumi Haldar ◽  
Achintya Kumar Dutta
Keyword(s):  
Electron Affinity ◽  
Electron Attachment ◽  
Equation Of Motion ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Coupled Cluster Method ◽  
Large Molecules ◽  
Layer Method ◽  
Speed Up ◽  
Attachment Process

We have presented a multi-layer implementation of the equation of motion coupled-cluster method for the electron affinity, based on local and pair natural orbitals. The method gives consistent accuracy for both localized and delocalized anionic states. It results in many fold speedup in computational timing as compared to the canonical and DLPNO based implementation of the EA-EOM-CCSD method. We have also developed an explicit fragment-based approach which can lead to even higher speed-up with little loss in accuracy. The multi-layer method can be used to treat the environmental effect of both bonded and non-bonded nature on the electron attachment process in large molecules.<br>

The Fock-Space Coupled-Cluster Method in the Calculation of Excited State Properties

2005 ◽  
Vol 70 (6) ◽  
pp. 811-825 ◽  
Author(s):  
Monika Musiał ◽  
Leszek Meissner
Keyword(s):  
Experimental Data ◽  
Excited States ◽  
Fock Space ◽  
Hamiltonian Formulation ◽  
Basis Sets ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Coupled Cluster Method ◽  
Excitation Energies ◽  
Equilibrium Geometries

Our recently developed intermediate Hamiltonian Fock-space coupled-cluster (FS-CC) method with singles and doubles is applied to calculation of equilibrium geometries, harmonic frequencies and adiabatic excitation energies for some excited states of N2 and CO. Due to the intermediate Hamiltonian formulation, which provides a robust computational scheme for solving the FS-CC equations, and the efficient factorization strategy, relatively large basis sets and reference spaces are employed permitting a comparison of calculated properties with experimental data.

scholarly journals Relativistic double-ionization equation-of-motion coupled-cluster method: Application to low-lying doubly ionized states

2020 ◽  
Vol 152 (10) ◽  
pp. 104302
Author(s):  
Himadri Pathak ◽  
Sudip Sasmal ◽  
Kaushik Talukdar ◽  
Malaya K. Nayak ◽  
Nayana Vaval ◽  
...  
Keyword(s):  
Equation Of Motion ◽  
Double Ionization ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Coupled Cluster Method
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