Computational Chemistry Wiki


13pages on
this wiki
Add New Page
Talk0 Share

Orca is a general purpose quantum chemistry program with emphasis in spectroscopy. It's free for academic use.

Written by Franck Neese

Methods included in version 2.6.35:

  • Semiempirical AM1, PM3, ZINDO, NDDO, MNDO
  • Hartree Fock theory (RHF, UHF, ROHF, CASSCF, SCS-MP2)
  • DFT including double hybrid functionals
  • Single reference: CCSD(T), QCISD(T), CEPA, CPF
  • Multi-reference: MRCI, MRMP2, MRMP3, MRMP4, MRACPF, MRAQCC, SORCI
  • Geometry optimization
  • Excited state calculations via TD-DFT and CI-singles (CIS).
  • Scalar relativistic ZORA, IORA and Douglas-Kroll-Hess (DKH)
  • COSMO model for solvent
  • Allows interface with existing QM/MM methods.

Spectroscopic Parameters:

  • Absorption and CD spectra from time-dependent DFT or MR-CI.
  • EPR-parameters: Zero-Field Splittings, g-tensors, hyperfine couplings, quadrupole tensors from Hartree-Fock, DFT and MR-CI. Scalar relativistic corrections at the ZORA level.
  • Mössbauer-parameters: isomer-shift and quadrupole splitting.
  • Exchange coupling constants from broken-symmetry DFT (and pathway analysis) or Difference-dedicated CI (DDCI).
  • NMR-parameters: chemical shifts from HF or DFT (but not with GIAO’s; IGLO is available)
  • IR / RAMAN spectra, isotope shifts via numerical frequency calculations (HF and DFT)
  • Simulation of absorption bandshapes and resonance-Raman excitation profiles from TD-DFT or MR-CI calculations

More information:


Ad blocker interference detected!

Wikia is a free-to-use site that makes money from advertising. We have a modified experience for viewers using ad blockers

Wikia is not accessible if you’ve made further modifications. Remove the custom ad blocker rule(s) and the page will load as expected.

Also on Fandom

Random Wiki