What is ReSpect

Re(lativistic) Spect(roscopy) program is a free, MPI parallelized computational chemistry program aimed at fast and reliable prediction of spectroscopic properties of closed- and open-shell molecules containing heavy elements. The molecular properties are accurately modeled with the full four-component Dirac-Coulomb (DC) Hamiltonian in order to include relativistic corrections variationally, and density functional theory (DFT) to account for correlation effects. The program also provides in-built all-electron basis sets suitable for relativistic calculations of all elements in the periodic table (Z=1-118), as well as several analysis and visualization tools. The most recent version of ReSpect allows to use/calculate


  • Hartree-Fock (HF)
  • Kohn-Sham Density Functional Theory (DFT) (available with LDA, GGA, hybrid and range-separated DFT functionals)
  • HF and DFT are implemented within Kramers restricted and unrestricted formalism


  • one-component Hamiltonian (with and without Douglas-Kroll-Hess one-electron corrections)
  • four-component scalar (spin-orbit free) Dirac-Coulomb Hamiltonian
  • four-component Dirac-Coulomb Hamiltonian including both scalar and spin-orbit corrections

First-order molecular properties

  • electronic g-tensor
  • hyperfine coupling A-tensor

Second-order molecular properties

  • nuclear spin-rotation constants
  • NMR shielding tensor (including restricted magnetic balance basis and GIAO orbitals)
  • indirect nuclear spin-spin coupling tensor (including restricted magnetic balance basis)

For additional informations about features implemented in the program, please read the manual.

Research highlight

Selected publications related to the ReSpect program:

Relativistic four-component calculations of indirect nuclear spin-spin couplings with efficient evaluation of the exchange-correlation response kernel; Křístková, Anežka; Komorovsky, Stanislav; Repisky, Michal; Malkin, Vladimir G.; Malkina, Olga L; Journal of Chemical Physics 2015, 142, 114102
jctc_2015-1Excitation Energies from Real-Time Propagation of the Four-Component Dirac–Kohn–Sham Equation; Repisky, Michal; Konecny, Lukas; Kadek, Marius; Komorovsky, Stanislav; Malkin, Olga L.; Malkin, Vladimir G.; Ruud, Kenneth; Journal of Chemical Theory and Computation 2015, 11 (3), pp 980–991
Communication: The absolute shielding scales of oxygen and sulfur revisited; Komorovsky, Stanislav; Repisky, Michal; Malkin, Elena; Ruud, Kenneth; Gauss, Jürgen; Journal of Chemical Physics 2015, 142, 091102
Implementation of the diagonalization-free algorithm in the self-consistent field procedure within the four-component relativistic scheme; Hrdá, Marcela;, Kulich, Tomáš; Repisky, Michal; Noga, Jozef; Malkina, Olga L.; Malkin, Vladimir G.; Journal of Computational Chemistry 2014, 35 (23), pp 1725–1737
3 Insight into the Mechanism of Carbonyl Hydrosilylation Catalyzed by Brookhart’s Cationic Iridium(III) Pincer ComplexMetsänen, Toni T.; Hrobárik, Peter; Klare, Hendrik F. T.; Kaupp, Martin; Oestreich, Martin; Journal of  The American Chemical Society, 2014, 136 (19), pp 6912–6915
2Cob(II)alamin: Relativistic DFT Analysis of the EPR Parameters; Demissie, Taye B.; Repisky, Michal; Liu, Hui; Ruud, Kenneth; Kozlowski, Pawel M.;  Joural of Chemical Theory Computation, 2014, 10 (5), pp 2125–2136
1Dismutational and Global-Minimum Isomers of Heavier 1,4-Dimetallatetrasilabenzenes of Group 14; Jana, Anukul; Huch, Volker; Repisky, Michal; Berger, Raphael J. F.; Scheschkewitz, David; Angewandte Chemie International Edition 2014, 54 (13), pp 3514–3518
Ab initio and relativistic DFT study of spin-rotation and NMR shielding constants in XF6 molecules, X = S, Se, Te, Mo, and W; Ruud, Kenneth; Demissie, Taye B.; Jaszuński, Michał; Journal of Chemical Physics 2014, 140 (19), 194308
Spin-rotation and NMR shielding constants in HClJaszuński, Michał;  Repisky, Michal; Demissie, Taye B.;  Komorovsky, Stanislav; Malkin, Elena; Ruud, Kenneth;  Garbacz, Piotr; Jackowski, Karol; Makulski, Włodzimierz; Journal of Chemical Physics 2013, 139, 234302
jp-2013-08389h_0007Four-component relativistic density functional theory calculations of NMR shielding tensors for paramagnetic systems; Komorovsky, Stanislav; Repisky, Michal; Ruud, Kenneth; Malkina, Olga L.; Malkin, Vladimir G.; Journal of Physical Chemistry A 2013, 117 (51), pp 14209–14219 
poc3157-toc-0001Four-component relativistic chemical shift calculations of halogenated organic compounds; Demissie, Taye B.; Repisky, Michal; Komorovsky, Stanislav; Isaksson, Johan; Svendsen, John S.; Dodziuk, Helena; Ruud, Kenneth; Journal of Physical Organic Chemistry 2013, 26 (8), pp 679–687 
jz-2012-02146m_0002The Absolute Shielding Constants of Heavy Nuclei: Resolving the Enigma of the Sn-119 Absolute Shielding; Malkin, Elena; Komorovsky, Stanislav; Repisky, Michal; Demissie, Taye B.; Ruud, Kenneth; Journal of Physical Chemistry Letters 2013, 4 (3), pp 459–463
ncontentA Combined Atomic Force Microscopy and Computational Approach for the Structural Elucidation of Breitfussin A and B: Highly Modified Halogenated Dipeptides from Thuiaria breitfussi; Hanssen, Kine Ø.; Schuler, Bruno; Williams, Antony J.; Demissie, Taye B.; Hansen, Espen; Andersen, Jeanette H.; Svenson, Johan; Blinov, Kirill; Repisky, Michal; Mohn, Fabian; Meyer, Gerhard; Svendsen, John-Sigurd; Ruud, Kenneth;  Elyashberg, Mikhail; Gross, Leo; Jaspars, Marcel; Isaksson, Johan; Angewandte Chemie International Edition 2012, 51 (49), pp 12238–12241
jp-2011-02327z_0004Relativistic Four-Component DFT Calculations of 1H NMR Chemical Shifts in Transition-Metal Hydride Complexes: Unusual High-Field Shifts Beyond the Buckingham–Stephens Model; Hrobarik, Peter; Hrobarikova, Veronika; Meier, Florian; Repisky, Michal; Komorovsky, Stanislav; Kaupp, Martin; Journal of Physical Chemistry A 2011, 115 (22), pp 5654–5659
Assessment of higher-order spin-orbit effects on electronic g-tensors of d(1) transition-metal complexes by relativistic two- and four-component methods; Hrobarik, Peter; Repisky, Michal; Komorovsky, Stanislav; Hrobarikova, Veronika; Kaupp, Martin; Theoritical Chemistry Accounts 2011, 129 (3-5), pp 715-725
Effects of finite size nuclei in relativistic four-component calculations of hyperfine structure; Malkin, Elena; Repisky, Michal; Komorovsky, Stanislav; Mach, Pavel; Malkina, Olga L.; Malkin, Vladimir G.; Journal of Chemical Physics 2011, 134 (4), 044111
Fully relativistic calculations of NMR shielding tensors using restricted magnetically balanced basis and gauge including atomic orbitals; Komorovsky, Stanislav; Repisky, Michal; Malkina, Olga L.; Malkin, Vladimir G.; Journal of Chemical Physics 2010, 132 (15), 154101
Relativistic four-component calculations of electronic g-tensors in the matrix Dirac-Kohn-Sham framework; Repisky, Michal; Komorovsky, Stanislav; Malkin, Elena; Malkina, Olga L.; Malkin, Vladimir G.; Chemical Physics Letters 2010, 488 (1-3), pp 94-97
Restricted magnetically balanced basis applied for relativistic calculations of indirect nuclear spin-spin coupling tensors in the matrix Dirac-Kohn-Sham framework; Repisky, Michal; Komorovsky, Stanislav; Malkina, Olga L.; Malkin, Vladimir G.; Chemical Physics 2009, 356 (1-3), pp 236-242
A fully relativistic method for calculation of nuclear magnetic shielding tensors with a restricted magnetically balanced basis in the framework of the matrix Dirac-Kohn-Sham equationKomorovsky, Stanislav; Repisky, Michal; Malkina, Olga L.; Malkin, Vladimir G.; Malkin-Ondík, Irina; Kaupp, Martin; Journal of Chemical Physics  2008, 128 (10), 104101