Implementation of transition moments between excited states in the approximate coupled-cluster singles and doubles model

2008 ◽  
Vol 129 (21) ◽  
pp. 214101 ◽  
Author(s):  
Mathias Pabst ◽  
Andreas Köhn
2013 ◽  
Vol 9 (S297) ◽  
pp. 344-348 ◽  
Author(s):  
R. C. Fortenberry

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.


2017 ◽  
Vol 13 (11) ◽  
pp. 5572-5581 ◽  
Author(s):  
J. Coleman Howard ◽  
James C. Womack ◽  
Jacek Dziedzic ◽  
Chris-Kriton Skylaris ◽  
Benjamin P. Pritchard ◽  
...  

Author(s):  
Fábris Kossoski ◽  
Antoine Marie ◽  
Anthony Scemama ◽  
Michel Caffarel ◽  
Pierre-François Loos

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

2019 ◽  
Author(s):  
Artur Nowak ◽  
Paweł Tecmer ◽  
Katharina Boguslawski

<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>


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