scholarly journals Variational coupled cluster for ground and excited states

2021 ◽  
Vol 155 (10) ◽  
pp. 104105
Author(s):  
Antoine Marie ◽  
Fábris Kossoski ◽  
Pierre-François Loos
Keyword(s):  
Excited States ◽  
Coupled Cluster

scholarly journals Theoretical Electronic and Rovibrational Studies for Anions of Interest to the DIBs

2013 ◽  
Vol 9 (S297) ◽  
pp. 344-348 ◽  
Author(s):  
R. C. Fortenberry
Keyword(s):  
Excited State ◽  
Excited States ◽  
State Of The Art ◽  
Spectroscopic Constants ◽  
Coupled Cluster ◽  
Electronic Excitations ◽  
Electronically Excited States ◽  
Coupled Cluster Theory ◽  
Electronically Excited ◽  
Enolate Anion

AbstractThe dipole-bound excited state of the methylene nitrile anion (CH2CN−) has been suggested as a candidate carrier for a diffuse interstellar band (DIB) at 803.8 nm. Its corresponding radical has been detected in the interstellar medium (ISM), making the existence for the anion possible. This work applies state-of-the-art ab initio methods such as coupled cluster theory to reproduce accurately the electronic excitations for CH2CN− and the similar methylene enolate anion, CH2CHO−. This same approach has been employed to indicate that 19 other anions may possess electronically excited states, five of which are valence in nature. Concurrently, in order to assist in the detection of these anions in the ISM, work has also been directed towards predicting vibrational frequencies and spectroscopic constants for these anions through the use of quartic force fields (QFFs). Theoretical rovibrational work on anions has thus far included studies of CH2CN−, C3H−, and is currently ongoing for similar systems.

scholarly journals Electronically Excited States in Solution via a Smooth Dielectric Model Combined with Equation-of-Motion Coupled Cluster Theory

2017 ◽  
Vol 13 (11) ◽  
pp. 5572-5581 ◽  
Author(s):  
J. Coleman Howard ◽  
James C. Womack ◽  
Jacek Dziedzic ◽  
Chris-Kriton Skylaris ◽  
Benjamin P. Pritchard ◽  
...  
Keyword(s):  
Excited States ◽  
Equation Of Motion ◽  
Coupled Cluster ◽  
Electronically Excited States ◽  
Coupled Cluster Theory ◽  
Cluster Theory ◽  
Dielectric Model ◽  
Electronically Excited

scholarly journals Excited States from State-Specific Orbital-Optimized Pair Coupled Cluster

2021 ◽  
Author(s):  
Fábris Kossoski ◽  
Antoine Marie ◽  
Anthony Scemama ◽  
Michel Caffarel ◽  
Pierre-François Loos
Keyword(s):  
Excited States ◽  
Coupled Cluster

scholarly journals Assessing the Accuracy of Simplified Coupled Cluster Methods for Electronic Excited States in F0 Actinide Compounds

2019 ◽  
Author(s):  
Artur Nowak ◽  
Paweł Tecmer ◽  
Katharina Boguslawski
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Excited States ◽  
Coupled Cluster ◽  
Electronic Excitations ◽  
Electronic Excited States ◽  
Benchmark Study ◽  
Double Electron ◽  
Different Types ◽  
Cluster Methods

<p>We present a benchmark study of the performance of various recently presented EOM-pCCD-based methods to model ground and excited state properties of a set of f0 actinide species that feature different types of electronic excitations, like local excitations or charge transfer. Our data suggests that the recently developed EOM-pCCD-LCCSD method outperforms conventional approaches like EOM-CCSD reducing the standard error by a factor of 2 (to 0.25 eV). Thus, EOM-pCCD-LCCSD can be considered as an alternative to model excited states in challenging systems, especially those who feature a double electron transfer for which EOM-CCSD typically fails.</p>

scholarly journals Dyson orbitals within the fc-CVS-EOM-CCSD framework: theory and application to X-ray photoelectron spectroscopy of ground and excited states

2020 ◽  
Vol 22 (5) ◽  
pp. 2693-2703 ◽  
Author(s):  
Marta L. Vidal ◽  
Anna I. Krylov ◽  
Sonia Coriani
Keyword(s):  
Excited States ◽  
Photoelectron Spectroscopy ◽  
Equation Of Motion ◽  
Coupled Cluster ◽  
Ionization Energies ◽  
X Ray

Ionization energies and Dyson orbitals within frozen-core core–valence separated equation-of-motion coupled cluster singles and doubles (fc-CVS-EOM-CCSD) enable efficient and reliable calculations of standard XPS and of UV-pump/XPS probe spectra.

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.

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