showing 6 related works from this author
Triple excitation effects in coupled cluster calculations of Verdet constants
2000
Abstract The CC3 approach has been employed to calculate the Verdet constants of N 2 ,C 2 H 2 , and CH 4 . For N 2 and C 2 H 2 , relatively large triples contributions are found which need to be included in order to reach close agreement with the experimental constants.
Critical analysis of the spin-rotation constants of CF2 and CCl2: A theoretical investigation
2005
Quantum chemical ab initio calculations for the spin-rotation constants of difluorocarbene (CF2) and dichlorocarbene (CCl2) were carried out using coupled-cluster techniques with sequences of correlation-consistent basis sets. Theoretical best estimates were obtained using extrapolation to the complete basis-set limit and taking into account corrections for core correlation, additional diffuse functions and zero-point vibrational effects. It is demonstrated that such accurate theoretical estimates can be used either to support or to challenge the analysis of the experimental spectra and the reliability of the resulting data. 2005 Elsevier B.V. All rights reserved.
The Dalton quantum chemistry program system
2013
Dalton is a powerful general-purpose program system for the study of molecular electronic structure at the Hartree-Fock, Kohn-Sham, multiconfigurational self-consistent-field, MOller-Plesset, confi ...
Accurate Nonlinear Optical Properties for Small Molecules
2006
During the last decade it became possible to calculate by quantum chemical ab initio methods not only static but also frequency-dependent properties with high accuracy. Today, the most important tools for such calculations are coupled cluster response methods in combination with systematic hierarchies of correlation consistent basis sets. Coupled cluster response methods combine a computationally efficient treatment of electron correlation with a qualitatively correct pole structure and frequency dispersion of the response functions. Both are improved systematically within a hierarchy of coupled cluster models. The present contribution reviews recent advances in the highly accurate calculat…
Zeeman effect in sulfur monoxide: A tool to probe magnetic fields in star forming regions
2017
[Context] Magnetic fields play a fundamental role in star formation processes and the best method to evaluate their intensity is to measure the Zeeman effect of atomic and molecular lines. However, a direct measurement of the Zeeman spectral pattern from interstellar molecular species is challenging due to the high sensitivity and high spectral resolution required. So far, the Zeeman effect has been detected unambiguously in star forming regions for very few non-masing species, such as OH and CN.
From Pentalene to Dicyclopenta[b,g]naphthalene, or the Change towards Delocalized Structures
2005
Lining triples-corrected coupled-cluster methods as well as other high-level theoretical approximations, the optimized parameters and isomerization barriers of the family of compounds cyclopentadiene-(benzene) x -cyclopentadiene (x 0, 1, 2) are computed. In contrast to previous studies, s-indacene presents a localized C 2 h geometry. Also, the localized structure of pentalene is found to be the most stable, but when two benzene rings are intercalated between the five-member rings of pentalene, the resulting molecule preferably adopts a delocalized D 2 h conformation.