• Absolute NMR shielding scales and nuclear spin–rotation constants in 175LuX and 197AuX (X= 19F, 35Cl, 79Br and 127I) 

      Demissie, Taye Beyene; Jaszuński, Michal; Komorovsky, Stanislav; Repisky, Michal; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-10-28)
      We present nuclear spin–rotation constants, absolute nuclear magnetic resonance (NMR) shielding constants, and shielding spans of all the nuclei in 175LuX and 197AuX (X = 19F, 35Cl, 79Br, 127I), calculated using coupled-cluster singles-and-doubles with a perturbative triples (CCSD(T)) correction theory, four-component relativistic density functional theory (relativistic DFT), and non-relativistic DFT. ...
    • Accurate X-ray Absorption Spectra near L- and M-Edges from Relativistic Four-Component Damped Response Time-Dependent Density Functional Theory 

      Konecny, Lukas; Vicha, Jan; Komorovsky, Stanislav; Ruud, Kenneth; Repisky, Michal (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-27)
      The simulation of X-ray absorption spectra requires both scalar and spin–orbit (SO) relativistic effects to be taken into account, particularly near L- and M-edges where the SO splitting of core p and d orbitals dominates. Four-component Dirac–Coulomb Hamiltonian-based linear damped response time-dependent density functional theory (4c-DR-TDDFT) calculates spectra directly for a selected frequency ...
    • Calculations of the EPR g-tensor using unrestricted two- and four-component relativistic approaches within the HF and DFT frameworks 

      Cherry, Peter J.; Komorovsky, Stanislav; Malkin, Vladimir G.; Malkina, Olga L. (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-06-08)
      Approaches and programs for calculations of the EPR g-tensor in the framework of the two- and four-component methods are still very rare. There are three main reasons for this: the wider community's unawareness of the importance of second- and higher order spin–orbit effects on the g-tensor, the methodological problems associated with performing such calculations and the lack of understanding of ...
    • Communication: The absolute shielding scales of oxygen and sulfur revisited 

      Komorovsky, Stanislav; Repisky, Michal; Malkin, Elena; Ruud, Kenneth; Gauss, Jürgen (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-03-04)
      We present an updated semi-experimental absolute shielding scale for the 17O and 33S nuclei. These new shielding scales are based on accurate rotational microwave data for the spin–rotation constants of H2 17O [Puzzarini et al., J. Chem. Phys. 131, 234304 (2009)], C17O [Cazzoli et al., Phys. Chem. Chem. Phys. 4, 3575 (2002)], and H2 33S [Helgaker et al., J. Chem. Phys. 139, 244308 (2013)] ...
    • Electron-Spin Structure and Metal-Ligand Bonding in Open-Shell Systems from Relativistic EPR and NMR: A Case Study of Square-Planar Iridium Catalysts 

      Bora, Pankaj L; Novotny, Jan; Ruud, Kenneth; Komorovsky, Stanislav; Marek, Radek (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-28)
      Electron and nuclear magnetic resonance spectroscopies are indispensable and powerful methods for investigating the molecular and electronic structures of open-shell systems. We demonstrate that the NMR and EPR parameters are extremely sensitive quantitative probes for the electronic spin density around heavy-metal atoms and the metal–ligand bonding. Using relativistic density-functional theory, we ...
    • Exact Two-Component TDDFT with Simple Two-Electron Picture-Change Corrections: X-ray Absorption Spectra Near L- and M-Edges of Four-Component Quality at Two-Component Cost 

      Konecny, Lukas; Komorovsky, Stanislav; Vicha, Jan; Ruud, Kenneth; Repisky, Michal (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-01)
      X-ray absorption spectroscopy (XAS) has gained popularity in recent years as it probes matter with high spatial and elemental sensitivities. However, the theoretical modeling of XAS is a challenging task since XAS spectra feature a fine structure due to scalar (SC) and spin–orbit (SO) relativistic effects, in particular near L and M absorption edges. While full four-component (4c) calculations of ...
    • Excitation Energies from Real-Time Propagation of the Four-Component Dirac–Kohn–Sham Equation 

      Repisky, Michal; Konecny, Lukas; Kadek, Marius; Komorovsky, Stanislav; Malkina, Olga L.; Malkin, Vladimir G.; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-01-21)
      We report the first implementation of real-time time-dependent density functional theory (RT-TDDFT) at the relativistic four-component level of theory. In contrast to the perturbative linear-response TDDFT approach (LR-TDDFT), the RT-TDDFT approach performs an explicit time propagation of the Dirac–Kohn–Sham density matrix, offering the possibility to simulate molecular spectroscopies involving ...
    • Experimental and four-component relativistic DFT studies of tungsten carbonyl complexes 

      Demissie, Taye Beyene; Kostenko, Nataliya; Komorovsky, Stanislav; Repisky, Michal; Isaksson, Johan; Bayer, Annette; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-07-24)
      We present a theoretical and experimental study of the structure and nuclear magnetic resonance (NMR) parameters of the pentacarbonyltungsten complexes of η<sup>1</sup>-2-(trimethylstannyl)-4,5-dimethylphosphinine, η<sup>2</sup>-norbornene, and imidazolidine-2-thione. The three complexes have a pseudo-octahedral molecular structure with the six ligands bonded to the tungsten atom. The η<sup>1</sup ...
    • The four-component DFT method for the calculation of the EPR g-tensor using a restricted magnetically balanced basis and London atomic orbitals 

      Misenkova, Debora; Lemken, Florian; Repisky, Michal; Noga, Jozef; Malkina, Olga L.; Komorovsky, Stanislav (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-28)
      ABSTRACT Four-component relativistic treatments of the electron paramagnetic resonance g-tensor have so far been based on a common gauge origin and a restricted kinetically balanced basis. The results of such calculations are prone to exhibit a dependence on the choice of the gauge origin for the vector potential associated with uniform magnetic field and a related dependence on the basis set ...
    • Four-component relativistic 31P NMR calculations for: Trans -platinum(ii) complexes: Importance of the solvent and dynamics in spectral simulations 

      Castro, Abril C.; Fliegl, Heike; Cascella, Michele; Helgaker, Trygve; Repisky, Michal; Komorovsky, Stanislav; Medrano, María Ángeles; Quiroga, Adoración G.; Swart, Marcel (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 = ...
    • Four-Component Relativistic Density Functional Theory Calculations of EPR g- and Hyperfine-Coupling Tensors Using Hybrid Functionals: Validation on Transition-Metal Complexes with Large Tensor Anisotropies and Higher-Order Spin-Orbit Effects 

      Gohr, Sebastian; Hrobárik, Peter; Repisky, Michal; Komorovsky, Stanislav; Ruud, Kenneth; Kaupp, Martin (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-12-04)
      The four-component matrix Dirac-Kohn-Sham (mDKS) implementation of EPR g- and hyperfine A-tensor calculations within a restricted kinetic balance framework in the ReSpect code has been extended to hybrid functionals. The methodology is validated for an extended set of small 4d1 and 5d1 [MEXn] q systems, and for a series of larger Ir(II) and Pt(III) d7 complexes (S=1/2) with particularly ...
    • Four-component relativistic density functional theory with the polarisable continuum model: application to EPR parameters and paramagnetic NMR shifts 

      Di Remigio, Roberto; Repisky, Michal; Komorovsky, Stanislav; Hrobárik, Peter; Frediani, Luca; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-01-01)
      The description of chemical phenomena in solution is as challenging as it is im- portant for the accurate calculation of molecular properties. Here, we present the implementation of the polarizable continuum model (PCM) in the four-component Dirac–Kohn–Sham density functional theory framework, o ↵ ering a cost-e ↵ ective way to concurrently model solvent and relativistic e ↵ ects. The ...
    • Four-Component Relativistic Density-Functional Theory Calculations of Nuclear Spin-Rotation Constants: Relativistic Effects in p-Block Hydrides 

      Komorovsky, Stanislav; Repisky, Michal; Malkin, Elena; Demissie, Taye Beyene; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-07-01)
      We present an implementation of the nuclear spin–rotation (SR) constants based on the relativistic four-component Dirac–Coulomb Hamiltonian. This formalism has been implemented in the framework of the Hartree–Fock and Kohn–Sham theory, allowing assessment of both pure and hybrid exchange–correlation functionals. In the density-functional theory (DFT) implementation of the response equations, a ...
    • Four-component relativistic time-dependent density-functional theory using a stable noncollinear DFT ansatz applicable to both closed- and open-shell systems 

      Komorovsky, Stanislav; Cherry, Peter J.; Repisky, Michal (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-14)
      We present a formulation of relativistic linear response time-dependent density functional theory for the calculation of electronic excitation energies in the framework of the four-component Dirac-Coulomb Hamiltonian. This approach is based on the noncollinear <i>ansatz</i> originally developed by Scalmani and Frisch [J. Chem. Theory Comput. 8, 2193 (2012)] and improves upon the past treatment of ...
    • How does relativity affect magnetically induced currents? 

      Berger, Raphael Johann Friedrich; Repisky, Michal; Komorovsky, Stanislav (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-07-23)
      Magnetically induced probability currents in molecules are studied in relativistic theory. Spin–orbit coupling (SOC) enhances the curvature and gives rise to a previously unobserved current cusp in AuH or small bulge-like distortions in HgH2 at the proton positions. The origin of this curvature is magnetically induced spin-density arising from SOC in the relativistic description.
    • Indirect NMR spin-spin coupling constants in diatomic alkali halides 

      Jaszuński, Michał; Antušek, Andrej; Demissie, Taye Beyene; Komorovsky, Stanislav; Repisky, Michal; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-12-28)
      We report the Nuclear Magnetic Resonance (NMR) spin–spin coupling constants for diatomic alkali halides MX, where M = Li, Na, K, Rb, or Cs and X = F, Cl, Br, or I. The coupling constants are determined by supplementing the non-relativistic coupled-cluster singles-and-doubles (CCSD) values with relativistic corrections evaluated at the four-component density-functional theory (DFT) level. These ...
    • Interpreting the paramagnetic NMR spectra of potential Ru(III) metallodrugs: synergy between experiment and relativistic DFT calculations 

      Novotný, Jan; Sojka, Martin; Komorovsky, Stanislav; Nečas, Marek; Marek, Radek (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-06-16)
      Ruthenium-based compounds are potential candidates for use as anticancer metallodrugs. The central ruthenium atom can be in the oxidation state +2 (e.g., RAPTA, RAED) or +3 (e.g., NAMI, KP). In this study we focus on paramagnetic NAMI analogs of a general structure [4-R-pyH]+ <i>trans</i>-[Ru<sup>III</sup>Cl<sub>4</sub>(DMSO)(4-R-py)]<sup>−</sup>, where 4-R-py stands for a 4-substituted pyridine. ...
    • Linking the Character of the Metal-Ligand Bond to the Ligand NMR Shielding in Transition-Metal Complexes: NMR Contributions from Spin-Orbit Coupling 

      Novotný, Jan; Vícha, Jan; Bora, Pankaj L.; Repisky, Michal; Straka, Michal; Komorovsky, Stanislav; Marek, Radek (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-07-06)
      Relativistic effects significantly affect various spectroscopic properties of compounds containing heavy elements. Particularly in Nuclear Magnetic Resonance (NMR) spectroscopy, the heavy atoms strongly influence the NMR shielding constants of neighboring light atoms. In this account we analyze paramagnetic contributions to NMR shielding constants and their modulation by relativistic spin–orbit ...
    • Relativistic DFT Calculations of Hyperfine Coupling Constants in 5d Hexafluorido Complexes: [ReF6]2- and [IrF6]2- 

      Haase, Pi A. B.; Repisky, Michal; Komorovsky, Stanislav; Bendix, Jesper; Sauer, Stephan P. A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-10-12)
      The performance of relativistic density functional theory (DFT) methods has been investigated for the calculation of the recently measured hyperfine coupling constants of hexafluorido complexes [ReF<sub>6</sub> ] <sup>2-</sup> and [IrF<sub>6</sub> ] <sup>2-</sup> . Three relativistic methods were employed at the DFT level of theory: the 2-component zeroth-order regular approximation ...
    • Relativistic four-component calculations of indirect nuclear spin-spin couplings with efficient evaluation of the exchange-correlation response kernel 

      Kristkova, Anezka; Komorovsky, Stanislav; Repisky, Michal; Malkin, Vladimir G.; Malkina, Olga L. (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-03-16)
      In this work, we report on the development and implementation of a new scheme for efficient calculation of indirect nuclear spin-spin couplings in the framework of four-component matrix Dirac-Kohn-Sham approach termed matrix Dirac-Kohn-Sham restricted magnetic balance resolution of identity for J and K, which takes advantage of the previous restricted magnetic balance formalism and the density ...