Ionization potential and excitation energy calculations forBa+using the relativistic coupled-cluster method

2001 ◽  
Vol 64 (3) ◽  
Author(s):  
Geetha Gopakumar ◽  
Holger Merlitz ◽  
Sonjoy Majumder ◽  
Rajat K. Chaudhuri ◽  
B. P. Das ◽  
...  
Keyword(s):  
Excitation Energy ◽  
Ionization Potential ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Coupled Cluster Method ◽  
Energy Calculations

scholarly journals EOM-CC Guide for Fock-Space Travel: The C2 Edition

2018 ◽  
Author(s):  
Sahil Gulania ◽  
Thomas-C. Jagau ◽  
Anna I. Krylov
Keyword(s):  
Electronic Structure ◽  
Ionization Potential ◽  
Fock Space ◽  
Wave Functions ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Space Travel ◽  
Electron Detachment ◽  
Coupled Cluster Method ◽  
Structure Calculations

Despite their small size, C<sub>2</sub> species pose a big challenge to electronic structure owing to extensive electronic degeneracies and multi-configurational wave functions leading to a dense manifold of electronic states. We present detailed electronic structure calculations of C<sub>2</sub>, C<sub>2</sub><sup>-</sup>, and C<sub>2</sub><sup>2-</sup> emphasizing spectroscopically relevant properties. We employ double ionization potential (DIP) and ionization potential (IP) variants of equation-of-motion coupled-cluster method with single and double substitutions (EOM-CCSD) and a dianionic reference state. We show that EOM-CCSD is capable of describing multiple interacting states in C<sub>2</sub> and C<sub>2</sub><sup>-</sup> in an accurate, robust, and effective way. We also characterize the electronic structure of C<sub>2</sub><sup>2-</sup>, which is metastable with respect to electron detachment.

scholarly journals EOM-CC Guide for Fock-Space Travel: The C2 Edition

2018 ◽  
Author(s):  
Sahil Gulania ◽  
Thomas-C. Jagau ◽  
Anna I. Krylov
Keyword(s):  
Electronic Structure ◽  
Ionization Potential ◽  
Fock Space ◽  
Wave Functions ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Space Travel ◽  
Electron Detachment ◽  
Coupled Cluster Method ◽  
Structure Calculations

Despite their small size, C<sub>2</sub> species pose a big challenge to electronic structure owing to extensive electronic degeneracies and multi-configurational wave functions leading to a dense manifold of electronic states. We present detailed electronic structure calculations of C<sub>2</sub>, C<sub>2</sub><sup>-</sup>, and C<sub>2</sub><sup>2-</sup> emphasizing spectroscopically relevant properties. We employ double ionization potential (DIP) and ionization potential (IP) variants of equation-of-motion coupled-cluster method with single and double substitutions (EOM-CCSD) and a dianionic reference state. We show that EOM-CCSD is capable of describing multiple interacting states in C<sub>2</sub> and C<sub>2</sub><sup>-</sup> in an accurate, robust, and effective way. We also characterize the electronic structure of C<sub>2</sub><sup>2-</sup>, which is metastable with respect to electron detachment.

The relativistic coupled-cluster method: transition energies of bismuth and eka-bismuth

1998 ◽  
Vol 94 (1) ◽  
pp. 181-187 ◽  
Author(s):  
EPHRAIM ELIAV ◽  
UZI KALDOR ◽  
YASUYUKI ISHIKAWA
Keyword(s):  
Cluster Method ◽  
Coupled Cluster ◽  
Coupled Cluster Method ◽  
Transition 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>

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