ReSpect (Relativitic Spectroscopy) is a free parallel computational chemistry program for relativistic calculations of spectroscopic parameters of atoms, molecules and solids. Since the underlying theory combines all-electron Kohn-Sham Density Functional Theory (DFT) with either modern exact two-component (X2C) Hamiltonian models or full four-component Dirac-Coulomb Hamiltonian, ReSpect offers unique capabilities in terms of accuracy and efficiency to study spectroscopic parameters of systems with heavy elements. The program also provides in-built all-electron basis sets of Gaussian-Type Orbitals (GTO) suitable for relativistic calculations of elements across the periodic table (Z=1-118).


Model Hamiltonians

  • Kohn-Sham (KS) - non-relativistic one-component
  • Hartree-Fock (HF) - non-relativistic one-component
  • Exact two-component (X2C) - relativistic two-component
  • modified Dirac-Kohn-Sham (mDKS) - relativistic four-component
  • modified Dirac-Hartree-Fock (mDHF) - relativistic four-component
  • all model Hamiltonians support Kramers restricted and unrestricted formalism

DFT Exchange-Correlation Functionals

  • pure DFT functionals of LDA & GGA type
  • hybrid and range-separated DFT functionals
  • non-collinear formulation of all DFT functionals
  • analytical potential and kernels for all DFT functionals
  • adaptive numerical integration grid

Molecular Spectroscopic Properties

  • Nuclear Magnetic Resonance (NMR) Spectroscopy
  • Paramagnetic Nuclear Magnetic Resonance (pNMR) Spectroscopy
  • Electron Paramagnetic/Spin Resonance (EPR/ESR) Spectroscopy
  • Electronic Circular Dichroism (ECD) Spectroscopy
  • UV/Vis and X-ray Absorption Spectroscopy
  • UV/Vis and X-ray Transient (Pump-Probe) Absorption Spectroscopy
  • Nuclear Spin-Rotation Constant
  • Nuclear Quadrupole Interactions (EFG)
  • Mössbauer Spectroscopy

Solid-state Spectroscopic Properties

  • Band-structure diagrams for any path in k-space
  • Z2 invariants for 2D systems
  • Rashba and Dresselhaus splittings
  • Nuclear quadrupole interactions (EFG)

Performance and Parallelization

  • Vectorized and parallel integral library (InteRest)
  • OpenMP and MPI parallel two-electron Fock library
  • Efficient and parallel XC numerical integration
  • Linear-scaling technology (integral screening, LinK)
  • RI-J technology for the Coulomb two-electron contribution

License and Distribution

ReSpect is distributed as proprietary software at no cost and is currently available as OpenMP parallel static binaries for Linux OS and x86_64 architecture. The program is limited to non-commercial, academic, and non-profit private use. More information regarding to the program license and distribution can be found here.

Latest Posts

Useful Links

Our Contacts

Hylleraas Centre
Department of Chemistry
UiT The Arctic University of Norway
Tromsø, NO-9037 Norway