About DFTB+

The DFTB+ code is the successor of the old DFTB and Dylax codes, which were developed in Paderborn in the group of Professor Frauenheim. It is developed in the same group (but now in Bremen in the Bremen Center for Computational Materials Science).

Features

The new code unifies most of the capabilities of those codes and extends them. Among others, it has the following capabilities:

• Non-scc and scc calculations (with expanded range of SCC accelerators)
  
  • Cluster/molecular systems
  • Periodic systems (arbitrary K-point sampling, band structure calc.)
• l-shell resolved calculations possible
• Spin polarised calculation (collinear spin)
• Geometry optimisation
  • Steepest descent
  • Conjugate gradient
• Geometry optimisation constraints (in xyz-coordinates)
• Molecular dynamics (Anderson thermostat)
• Improved finite temperature calculations
• Dispersion correction (van der Waals interaction)
• Ability to treat f-electrons
• LDA+U extension
• QM/MM coupling with external point charges (smoothing possible)
• OpenMP parallelisation
• Automatic code validation (autotest system)
• New user friendly, extensible input format (HSD or XML)
• Dynamic memory allocation
• Additional tool for generating cube files for charge distribution, molecular orbitals, etc. (Waveplot)

The current stable release is Version 1.0.1.

DFTB+ is being developed and extended continuously. We are planning to issue a major release every sixth month. The following features are considered to become part of the next releases. (Please note, that those plans could be changed depending on the research interests of the developers, the collaborating groups and the user community.)

Version 1.1

• Electronic constraints
• Collinear spin-orbit coupling
• Extended LDA+U and pseudo self interaction correction
• Embedding with DFTB+ (APIs for obtaining DFTB energies, forces etc.)
• Improved dispersion models
• New Slater-Koster files with more data and with compatibility check
• Improved range of thermostats
• Integration constraints with SHAKE or RATTLE
• Calculation of vibrations (with numerical 2nd derivatives)
• Damped SCC interaction for hydrogen

Version 1.2

• Integration of existing linear response and time dependant DFTB
• Divide and conquer linear scaling
• Improvements in the electrostatic code for large systems (PME)
• Full non-collinear spin
• Forces on lattice vectors (cell optimisation)
• Analytical second derivatives
• BFGS geometry optimisation

Version 1.3

• Spin dynamics
• Internal coordinates
• Extension of GW and linear response to arbitrary k-points