# Features

### From Diracwiki

## 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: 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.

- New mailing lists for help and announcements about the DIRAC program package

- 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

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

- Hamiltonians
- 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

- Efficiency
- 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)

- Methods:
- 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 (see http://tc03.fkt.bme.hu/)
- frozen density embedding

- Hamiltonians:
- 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:
- visualization of unperturbed and perturbed densities
- projection analysis of expectation values
- expectation values/transition moments KRCI/GOSCI

## Features in DIRAC08

- Methods:
- Hartree-Fock
- Density Functional Theory
- Coupled Cluster
- Configuration Interaction
- Second order MÃ¸ller-Plesset Perturbation Theory

- Hamiltonians:
- 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.

- Efficiency:
- 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