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New features in DIRAC21

  • Molecular rotational g-tensors. Contributor: I. Agustín Aucar.
  • ExaCorr GPU-aware parallel coupled cluster module. Contributors: Johann V. Pototschnig, Anastasios Papadopoulos, Dmitry I. Lyakh, Michal Repisky, Loïc Halbert, André Severo Pereira Gomes, Hans Jørgen Aa. Jensen, Lucas Visscher.
    • Reference: J. V. Pototschnig, A. Papadopoulos, D. I. Lyakh, M. Repisky, L. Halbert, A. S. P. Gomes, H. J. Aa. Jensen, L. Visscher. Implementation of relativistic coupled cluster theory for massively parallel GPU-accelerated computing architectures. arXiv:2103.08473 [physics.chem-ph]
    • Manual: "**EXACC"
  • Atomic supersymmetry. Contributors: A. Sunaga and T. Saue
  • Beyond the electric-dipole approximation When calculating excitation energies at the Hartree-Fock or Kohn-Sham levels, intensities can be calculated using the full semi-classical light-matter interaction as well as truncated interaction to arbitrary order in the wave vector in both the length and velocity representation. Rotational average is provided by default, but specific orientations can also be chosen. Contributors: Nanna H. List and Trond Saue
    • Reference: Nanna Holmgaard List, Timothé Romain Léo Melin, Martin van Horn and Trond Saue: Beyond the electric-dipole approximation in simulations of X-ray absorption spectroscopy: Lessons from relativistic theory, J. Chem. Phys. 152 (2020) 184110
    • Manual: ".BED"
    • Tutorial: coming soon
Revised features in DIRAC21
  • Gauge origin, dipole origin, and phase origin (.GAUGEO alias .GO ANG, .DIPORG, and .PHASEO, respectively) can now ONLY be set under **HAMILTONIAN.
New Interfaces
  • Interface to ROSE (Localized Orbitals). Main contributor: Bruno Senjean.
  • Extract DIRAC data to Python (see utils/ Contributor: L. Visscher.
  • Significantly improved performance of GASCIP configuration interaction module. Contributor: Hans Jørgen Aa. Jensen
Change of defaults
  • The format of the DFCOEF coefficient file has changed. You can convert old-style files to the new format using the utility routine cf_addlabels.x found in the the build directory after make.
  • The CODATA2018 set of physical constants is now used as default. Values are taken from NIST web page ( Before DIRAC21, values from CODATA1998 were default. New keyword was implemented to select the desired set of data. Contributor: Agustín Aucar
  • In the compilation step OpenMP is now enabled by default.
  • One-electron operator ANGMOM's origin was moved from gauge-origin to the molecular center of mass.
Known issues
  • Atomic supersymmetry does not work in combination with the molecular-mean-field X2C approach.
  • ExaTensor (ExaCorr module) doesn't raise an error if it runs out of memory, but hangs

New features in DIRAC19

  • EOMCC - core excitation and ionization energies via core-valence separation using projectors in RELCC (Avijit Shee, Andre Gomes, Marta Lopez Vidal)
    • Reference: L. Halbert, M. L. Vidal, A. Shee, S. Coriani, A. S. P. Gomes Relativistic EOM-CCSD for Core-Excited and Core-Ionized State Energies Based on the Four-Component Dirac–Coulomb(−Gaunt) HamiltonianJ. Chem. Theory Comput. 17 (2021), 3583
    • Manual: see keywords under "*CCPROJ"
  • Python interface of DIRAC with Openfermion (Bruno Senjean) to perform relativistic quantum chemistry calculations simulated on a quantum computer .
  • Nuclear Spin-Rotation tensors. Contributors: I. Agustin Aucar and Trond Saue.
  • Nuclear Magnetic-Quadrupole-Moment interaction constant in KRCI (Malaya K. Nayak)
    • Reference: T. Fleig, M. K. Nayak and M. G. Kozlov TaN, a molecular system for probing P,T-violating hadron physics.Phys. Rev. A 93 (2016) 012505
  • Improved root tracking for EOM-CC (Luuk)
  • Use Kramers conjugation on doubly degenerate CI vectors in GASCIP code (cuts time for CI in half for ESR doublets) (Hans Jørgen)
  • DFT magnetizatibilities with LAOS and symmetry (Gosia Oejniczak and Trond Saue)
  • Resolved runtime issues in KRCI property modules (Malaya K. Nayak)
Change of defaults
  • Upgrade to python3

New features in DIRAC18

  • DFT magnetizabilities. Contributors: M. Olejniczak and Trond Saue.
    • Limitations: Magnetizabilities and NMR shieldings calculated at the DFT level are so far restricted to C1 symmetry, but we expect to fix this soon.
  • Enhancements to the frozen density embedding (FDE) functionality
  • Equation of motion coupled cluster
    • Energies for electronic excitations (EE), electron attachment (EA) and electron detachment (IP), see ".EOMCC", "*EOMCC" and "*CCDIAG" entries of the manual for details. Contributiors: A. Shee, T. Saue, L. Visscher, A. S. P. Gomes
      • References:
        • A. Shee, T. Saue, L. Visscher, A. S. P. Gomes Equation-of-motion coupled-cluster theory based on the 4-component Dirac-Coulomb(-Gaunt) Hamiltonian. Energies for single electron detachment, attachment, and electronically excited states. J. Chem. Phys. 149 (2018) 174113
  • Polarized embedding can be done with xyz-files. Contributor: Trond Saue
  • Improved quaternion diagonalization Contributor: H. J. Aa. Jensen
  • Improvements in the visualization module (**VISUAL) Contributors: M. Olejniczak and T. Saue.
    • the possibility to calculate the NMR shielding tensor in a selected point in space, see ".NICS"
    • the possibility to visualize various densities on an imported 3D grid, see ".3D_IMP"
    • the possibility to calculate magnetic properties densities using the imported magnetically-induced current density, see ".READJB"
    • the possibility to scale densities by Cartesian products xiyjzk, see ".CARPOW"
    • the possibility to generate and visualize radial distributions, see ".RADIAL"
Change of defaults
  • New convergence criterium for CC amplitude equation: The convergence criterium for the amplitude equations that determine the CC energy has been revised and made consistent with the criterium used in the lambda equations used for molecular properties. In both cases we now take the norm of the differences between amplitudes of subsequent iterations. In practice this typically means the program will use a few iterations less. For normal calculations this is of no consequence as the default is still to converge very tightly, but if extremely high precision is required one may need to check the achieved convergence.
  • Change in the reorthonormalization terms in the calculation of magnetic properties with London atomic orbitals: the reorthonormalization and response contributions involve the same orbital pairs, for instance if all rotations between occupied and virtual orbitals are present in response equations, the reorthonormalization terms are also constructed from all orbital blocks; the keywords .DOEPRN and .NOEPRN under *NMR are depreciated;

New features in DIRAC17

  • New ”.MVOFAC” option in *KRMC input section for Modified Virtual Orbitals in MCSCF. Contributor: H. J. Aa. Jensen.
  • New and numerically stable procedure for elimination/freezing of orbitals at SCF level. Contributor: T. Saue.
  • Support for use of DIRAC in PyADF and QMFlows workflow engines. Contributors: Lucas Visscher, Andre Gomes and Christoph Jacob
  • New easier options for point charges in the .mol file: “LARGE POINTCHARGE” or “LARGE NOBASIS” (the two choices are equivalent), see here
  • Provided memory counter for RelCC calculations, suitable for memory consuming large scale Coupled Cluster calculations, see here for details. Contributor: Miroslav Iliaš
  • Write out effective Hamiltonian in Fock space coupled cluster to a file for post processing. Can be used with external code of Andrei Zaitsevskii (St. Petersburg).
  • Restart for RELCCSD. Contributor: Andre Gomes. See the keyword .RESTART and the section *CCRESTART
Performance Improvements
  • Restored integral screening. Contributor: Hans Jørgen Aagaard Jensen
  • POLPRP module + Davidson diagonalizer now parallel. Contributor: Markus Pernpointner
  • Fixed errors for quaternion symmetries in 2-electron MO integrals used in CI calculations with GASCIP. It is now possible to do CI calculations with GASCIP for C1 symmetry (i.e. no symmetry).
  • Fixed error for parallel complex CI or MCSCF with GASCIP
  • Fixed compilation of XCFun on Mac OS X High Sierra.
Change of defaults
  • Change of final (open shell) orbital energies + SCF cycle modification. Contributors: Hans Jørgen Aagaard Jensen and Trond Saue
  • .SKIPEP is now default for KR-MCSCF, new keyword .WITHEP to include e-p rotations
Basis set news
  • Added the RPF-4Z and aug-RPF-4Z basis sets for f-elements to the already existing files with sets for s, p and d elements. Deleted the aug-RPF-3Z set as that was not an official set.
  • Fixed the p exponents for Na in the dyall 4z basis sets to match the archive. The changes are small so should not significantly affect results.
  • Updated basis_dalton/ with basis set updates in the Dalton distribution:
    • fix of errors in Ahlrichs-pVDZ (several diffuse exponents were a factor 10 too big)
    • fix of errors for 2. row atoms in aug-cc-pCV5Z
    • added many atoms to aug-cc-PVTZ_J
    • added many Frank Jensen “pc” type basis sets
    • added Turbomole “def2” type basis sets

New features in DIRAC16

  • RELCCSD expectation values. For more information, see J. Chem. Phys. 145 (2016) 184107 as well as test/cc_gradient for an example.
  • Improved start potential for SCF: sum of atomic LDA potentials, generated by GRASP.
Change of defaults
  • Negative denominators (e.g. appearing in core ionized systems) accepted in RELCCSD
  • AOFOCK is now default if at least 25 MPI nodes (parallelizes better than SOFOCK). And .AOFOCK documented.
  • Error corrections and updates in isotope properties for the following atoms:
    • Br isotope 2: quadrupole moment .2620 → .2615
    • Ag isotope 2: magnetic moment .130563 → -.130691 (note sign change)
    • In isotope 2: quadrupole moment .790 → .799
    • Nd magnetic moments of isotopes 4 and 5 were interchanged: -0.065 → -1.065 and -1.065 → -0.065
    • Gd: quadrupole moments of isotopes 4 and 5 updated: 1.36 → 1.35 and 1.30 → 1.27
    • Ho isotope 1: quadrupole moment updated 3.49 → 3.58
    • Lu isotope 2: quadrupole moment updtaed 4.92 → 4.97
    • Hf isotope 1: mass was real*4, not real*8, thus 7 digits instead of 179.9465457D0 (i.e. approx 179.9465)
    • Ta isotope 1: quadrupole moment added 0.00 → 3,17
    • Tl isotope 1: nuclear moment 1.63831461D0 → 1.63821461D0 (typo, error 1.d-4)
    • Pb isotope 3: nuclear moment 0.582583D0 → 0.592583D0 (typo, error 1.d-2)
    • Po isotope 1: nuclear moment added: 0.000 → 0.688
  • For other bug fixes compared to DIRAC15 we refer to CHANGELOG.rst in the main directory of the Dirac distribution.

New features in DIRAC15

  • FanoADC-Stieltjes: Calculation of decay widths of electronic decay processes. For more information see JCP 142, 144106 (2015).
  • DIRRCI expectation values, see test/dirrci_property for an example.
  • Geometry optimization with xyz input, see test/geo_opt_xyz for an example
  • KR-MCSCF: Performance improvements for determinant generation in GASCIP
Basis set news
  • Relativistic prolapse-free Gaussian basis sets of quadruple-zeta quality: RPF-4Z, aug-RPF-4Z
  • ANO-RCC basis:
    • Fixed Carbon basis set (wrong contraction coefficients, see [MOLCAS ANO-RCC](
    • Modified the 3 Th h-functions by replacing them with the 3 Ac h-functions to Th.
  • Fixed reading of ANO-RCC and ANO-DK3 basis sets from the included basis set library.
New defaults
  • For open-shell SCF calculations, .OPENFAC = 0.5 by default, as this seems to improve convergence. Final orbital energies are recalculated with .OPENFAC 1.0, for IP interpretation.
Improved compilation and testing

New features in DIRAC14

  • Intrinsic Atomic Orbitals (IAOs), as formulated by Gerald Knizia, have been implemented to eliminate the polarization contribution in projection analysis.
  • The Polarizable Continuum Model (PCM) is available for the inclusion of solvent effects. For more details, see this paper
  • As a byproduct of the PCM implementation, molecular electrostatic potential (MEP) maps are available for 4-component electronic-structure calculations, see this paper
  • +Q corrections (size-consistency corrections) for KR-CI calculations
  • Extended Hückel method using atomic fragments for SCF start guess (alternative to atomic start)

New features in DIRAC13

Improved compilation and testing

  • Support for Windows 7/8 with GNU MinGW32/64 suite and native math libraries
  • New test script
  • Simplified testing using MPI
  • Updated math library detection
  • Better support for MKL libraries
  • Support for Cray
  • Support for MPI runs which do not use mpirun

New defaults

  • The pam script sets (unless these variables are set by the user):

New features in DIRAC12 (released 12/12/12)

New defaults

  • New input style for RELCC and RELADC
  • Changed level shift
  • Changed bare nucleus corrections (new parameters)
  • New MPI 64/32-interface
  • Improved start guess and improved SCF convergence

New features in DIRAC11 (released 11/11/11)

  • Analytic molecular gradient at the DFT level
  • New and fast XC integration
  • Functional derivatives using automatic differentiation (XCFun)
  • New visualization options
  • RKBIMP: MO-coefficients generated using restricted kinetic balance (RKB) can be extended by their unrestricted kinetic balance (UKB) complement, thus providing magnetic balance for response calculations involving external magnetic fields
  • New and improved 2c Hamiltonian schemes

New build system and infrastructure

  • New compilation scheme: configure replaced by CMake mechanism
  • New pam script (python)
  • Alternative launcher: (python)
  • New testing framework based on python (runscript)
  • Many static allocation calls replaced by dynamic allocation; in practice this means that you may need less WORK array memory and/or more space for dynamic allocation compared to DIRAC10.

New mailing list

Important input changes

  • XC GRID has own input section
  • .DHF is now .SCF

Changed defaults

  • .LVCORR is now default; you can force explicit evaluation of (SS|SS) integrals with .DOSSSS


  • Hartree-Fock
  • Density Functional Theory
  • Kramers-restricted Multi-Configuration Self-Consistent-Field
  • Coupled Cluster
  • Configuration Interaction
  • Moeller-Plesset Perturbation Theory


  • 4c Dirac-Coulomb (includes scalar relativistic effects and spin-own-orbit coupling)
  • 4c Dirac-Coulomb-Gaunt (only HF; includes also spin-other-orbit coupling)
  • 4c spin-free Dirac-Coulomb (scalar relativistic effects only)
  • 4c Levy-Leblond (nonrelativistic)
  • 2c X2C, the one-step exact two-component Hamiltonian
  • 2c BSS, the two-step exact two-component Hamiltonian (= DKH(infinity,0))
  • 2c molecular-mean-field (= X2Cmmf), X2C transformation with the converged 4c-Fock operator as defining Hamiltonian

Molecular properties

  • Up to quadratic response properties at the HF and DFT level
  • First-order properties with MP2
  • Core excitation energies in the static exchange (STEX) approximation
  • Ionization energies at the ADC(3) level of theory
  • Selected first-order properties with CI


  • Full symmetry handling for linear molecules (otherwise up to D2h)
  • Parallelization using MPI library calls (MPI should be pre-installed)

New features in DIRAC10 (released 10/10/10)


  • Kramers-restricted MCSCF
  • RELADC for correlated calculations of single/double ionization spectra
  • large-scale parallel CI (LUCITA/KRCI)
  • intermediate Hamiltonian formalism for Fock-space CCSD
  • interface to MRCC
  • frozen density embedding


  • 2c X2C+AMFI for 2-electron spin-orbit corrections (spin-same orbit[SSO]/spin other-orbit[SOO])

Molecular properties

  • HF/KS excitation energies
  • KS response with noncollinear spin polarization and full derivative of functionals
  • linear response functions at imaginary frequencies
  • more efficient KS DFT code
  • London orbitals for HF NMR shieldings

Analysis tools

  • visualization of unperturbed and perturbed densities
  • projection analysis of expectation values
  • expectation values/transition moments KRCI/GOSCI

Features in DIRAC08


  • Hartree-Fock
  • Density Functional Theory
  • Coupled Cluster
  • Configuration Interaction
  • Second order Moller-Plesset Perturbation Theory


  • 4c Dirac-Coulomb (includes scalar relativistic effects and spin-own-orbit coupling)
  • 4c Dirac-Coulomb-Gaunt (includes also spin-other-orbit coupling) (only HF)
  • 4c spin-free Dirac-Coulomb (scalar relativistic effects only)
  • 4c Levy-Leblond (nonrelativistic)
  • 2c X2C, the one-step exact two-component Hamiltonian
  • 2c BSS, the two-step exact two-component Hamiltonian (= DKH(infinity,0))

Molecular properties

  • Up to quadratic response properties at the Hartree-Fock and DFT level
  • First order properties with MP2
  • Core excitation energies in the static exchange (STEX) approximation.
  • Single/Double Ionization energies and spectra at the ADC(3)/ADC(2x) level of theory.


  • Full symmetry handling for linear molecules (otherwise up to D2h)
  • Parallelization using MPI library calls (MPI should be preinstalled)

Some of the new features of DIRAC08

  • A one-step exact two-component Hamiltonian (X2C)
  • Relativistic Green's function (propagator) module RELADC for the calculation of ionization energies
  • Possibility to include the Gaunt interaction in HF calculations
  • Implementation of several new density functionals
  • Linear and quadratic response DFT
  • Addition of the latest Dyall basis sets and more non-relativistic basis sets to the basis library
  • Analysis by means of fragment orbitals
  • New parallelization of the MOLTRA module with reduced I/O
  • Parallelization of the LUCITA CI module
features.txt · Last modified: 2021/09/17 10:13 by aspg