English
norskBlar i forfatter "Helgaker, Trygve"
Viser treff 1-6 av 6
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Analytic cubic and quartic force fields using density-functional theory
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014) -
Dalton Project: A Python platform for molecular- and electronic-structure simulations of complex systems
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-05)The <i>Dalton Project</i> provides a uniform platform access to the underlying full-fledged quantum chemistry codes Dalton and LSDalton as well as the PyFraME package for automatized fragmentation and parameterization of complex molecular environments. The platform is written in Python and defines a means for library communication and interaction. Intermediate data such as integrals are exposed to ... -
The Dalton quantum chemistry program system
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014-05)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, Møller–Plesset, configuration-interaction, and coupled-cluster levels of theory. Apart from the total energy, a wide variety of molecular properties may be calculated using these electronic-structure models. Molecular gradients ... -
First-Principles Calculation of 1H NMR Chemical Shifts of Complex Metal Polyhydrides: The Essential Inclusion of Relativity and Dynamics
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-23)<sup>1</sup>H NMR spectroscopy has become an important technique for the characterization of transition-metal hydride complexes, whose metal-bound hydrides are often difficult to locate by X-ray diffraction. In this regard, the accurate prediction of <sup>1</sup>H NMR chemical shifts provides a useful, but challenging, strategy to help in the interpretation of the experimental spectra. In this work, ... -
Four-component relativistic 31P NMR calculations for: Trans -platinum(ii) complexes: Importance of the solvent and dynamics in spectral simulations
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-03-18)We report a combined experimental-theoretical study on the 31P NMR chemical shift for a number of trans-platinum(II) complexes. Validity and reliability of the 31P NMR chemical shift calculations are examined by comparing with the experimental data. A successful computational protocol for the accurate prediction of the 31P NMR chemical shifts was established for trans-[PtCl2(dma)PPh3] (dma = ... -
Relativistic four-component calculations of Buckingham birefringence using London atomic orbitals
(Journal article; Tidsskriftartikkel; Peer reviewed, 2011)We present the first relativistic study of the electric-field-gradient induced birefringence (Buckingham birefringence), with application to the series of molecules CX2 (X = O, S, Se, Te). A recently developed atomic-orbital-driven scheme for the calculation of time-dependent molecular properties using one-, two- and four-component relativistic wave functions (Bast et al. in Chem Phys 356:177, 2009) ...
