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]
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
Gauge origin, dipole origin, and phase origin (.GAUGEO alias .GO ANG, .DIPORG, and .PHASEO, respectively) can now ONLY be set under **HAMILTONIAN.
Interface to ROSE (Localized Orbitals). Main contributor: Bruno Senjean.
Reference: B. Senjean, S. Sen, M. Repisky, G. Knizia, L. Visscher. Generalization of Intrinsic Orbitals to Kramers-Paired Quaternion Spinors, Molecular Fragments, and Valence Virtual Spinors.J. Chem. Theory Comput. 17 (2021) 1337–1354
Extract DIRAC data to Python (see utils/dirac_data.py). 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 (http://physics.nist.gov/constants). 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.
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
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.
Reference: I. A. Aucar, S. S. Gómez, M. C. Ruiz de Azúa, and C. G. Giribet. Theoretical study of the nuclear spin-molecular rotation coupling for relativistic electrons and non-relativistic nuclei.J. Chem. Phys. 136 (2012) 204119
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
FDE contributions to magnetic properties (NMR shieldings, indirect spin-spin coupling constants, magnetizabilities), see ".FDE" and "*FDE" entries of the manual for details. Contributors: M. Olejniczak, R. Bast, A. S. P. Gomes
FDE interaction energies with CCSD, MP2 and mean-field densities. Contributors: M. Olejniczak, A. Shee, R. Bast, A. S. P. Gomes
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
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
Kramers-restricted Polarization Propagator in the ADC framework for electronic excitations, activated with ”.POLPRP”.
M. Pernpointner, L. Visscher and A. B. Trofimov. Four-component Polarization Propagator Calculations of Electron Excitations: Spectroscopic Implications of Spin-Orbit Coupling Effects.J. Chem. Theory Comput. 14, 1510 (2017).
Reference: M. Denis, M. Nørby, H. J. Aa . Jensen, A. S. P. Gomes, M. K. Nayak, S. Knecht, and T. Fleig. Theoretical study on ThF+, a prospective system in search of time-reversal violation.New J. Phys., 17:043005, 2015
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: wrapper.py (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.