Transition moments and excited-state first-order properties in the coupled-cluster model CC2 using the resolution-of-the-identity approximation

2002 ◽  
Vol 117 (15) ◽  
pp. 6939-6951 ◽  
Author(s):  
Christof Hättig ◽  
Andreas Köhn
Keyword(s):  
Excited State ◽  
Cluster Model ◽  
Coupled Cluster ◽  
First Order ◽  
Transition Moments ◽  
Resolution Of The Identity

Large scale polarizability calculations using the approximate coupled cluster model CC2 and MP2 combined with the resolution-of-the-identity approximation

2012 ◽  
Vol 136 (17) ◽  
pp. 174106 ◽  
Author(s):  
Daniel H. Friese ◽  
Nina O. C. Winter ◽  
Patrick Balzerowski ◽  
Raffael Schwan ◽  
Christof Hättig
Keyword(s):  
Cluster Model ◽  
Large Scale ◽  
Coupled Cluster ◽  
Resolution Of The Identity

scholarly journals Numerical Solution of the Spinor-Spinor Bethe-Salpeter Equation in Functional Nonlinear Spinor Theory

1975 ◽  
Vol 30 (5) ◽  
pp. 656-671
Author(s):  
W. Bauhoff
Keyword(s):  
Angular Momentum ◽  
Excited State ◽  
Variational Method ◽  
Numerical Solution ◽  
High Precision ◽  
Nonlinear Spinor ◽  
Spinor Theory ◽  
First Order ◽  
Scalar Mesons ◽  
Functional Methods

AbstractThe mass eigenvalue equation for mesons in nonlinear spinor theory is derived by functional methods. In second order it leads to a spinorial Bethe-Salpeter equation. This is solved by a variational method with high precision for arbitrary angular momentum. The results for scalar mesons show a shift of the first order results, obtained earlier. The agreement with experiment is improved thereby. An excited state corresponding to the η' is found. A calculation of a Regge trajectory is included,too.

Inclusion of the (T) triples correction into the linear-r12 corrected coupled-cluster model CCSD(R12)

2006 ◽  
Vol 106 (11) ◽  
pp. 2306-2317 ◽  
Author(s):  
Heike Fliegl ◽  
Christof Hättig ◽  
Wim Klopper
Keyword(s):  
Cluster Model ◽  
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 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>

First-order one-electron properties in the integral-direct coupled cluster singles and doubles model

1997 ◽  
Vol 107 (3) ◽  
pp. 849-866 ◽  
Author(s):  
Asger Halkier ◽  
Henrik Koch ◽  
Ove Christiansen ◽  
Poul Jo/rgensen ◽  
Trygve Helgaker
Keyword(s):  
Coupled Cluster ◽  
First Order
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