Capabilities

Capabilities

CASTEP is a full-featured materials modelling code based on a first-principles quantum mechanical description of electrons and nuclei. It uses the robust methods of a plane-wave basis set and pseudopotentials.

CASTEP allows the calculation of many properties, with a variety of tools as the users disposal.

Hamiltonians

• DFT XC-functionals
  • Local density approximation (LDA) (reference)
  • Generalised gradient approximation: PW91 (reference)
  • Generalised gradient approximation: PBE (reference)
  • Generalised gradient approximation: RPBE (reference)
  • Generalised gradient approximation: PBEsol (reference)
  • Generalised gradient approximation: WC (reference)
  • Meta-GGA: rSCAN (reference)
• Hybrid functionals
  • Hartree-Fock with PBE (PBE0) (reference)
  • Becke exchange with LYP correlation (B3LYP) (reference)
  • Screened exchange (sX-LDA) : (reference)
  • The HSE family of functionals (including user-defined parameterisation) : (reference)
• LDA+U
  • Hubbard DFT+U functionals : (reference)
• Semi-empirical dispersion corrections:
  • DFT+D (DFT+D, DFT+MBD) - TS, MBD, Grimme (D2, D3, D4), XDM
  • nterface to LibXC library of functionals (reference)

Structural Methods

• Full variable-cell geometry optimisation using BFGS, LBFGS and TPSD
• Geometry optimisation using internal co-ordinates
• Geometry optimisation using damped molecular dynamics
• Transition-state search using LST/QST method or NEB

Moleclar Dynamics

• Molecular Dynamics including fixed and variable-cell MD
• NVE, NVT, NPH and NPT ensembles
• Path-integral MD for quantum nuclear motion

Vibrational Spectroscopy

• Phonon dispersion and DOS over full Brillouin-Zone using DFPT methods
• Phonon dispersion and DOS over full Brillouin-Zone using supercell methods
• IR and raman intensities

Magnetic Resonance spectroscopy

• Chemical Shifts
• Electric Field Gradient tensors
• J-coupling
• Hyperfine and g-tensors

Optical and other Spectroscpies

• EELS/ELNES and XANES Spectra
• Optical matrix elements and spectra

Electronic Properties

• Band-structure calculations
• Mulliken population analysis
• Hirshfeld population analysis
• Electron Localisation Functions (ELF)

Pseudopotentials

• Supports Vanderbilt ultrasoft and norm-conserving pseudopotentials
• Built in "On The Fly" pseudopotential generator
• (non self-consistent) PAW for properties calculations

Electronic Solvers

• Block Davidson solver with density mixing
• Ensemble DFT for metals

Code and Parallelism

• Runs on machines from a PC to a supercomputer
• Modern code written in modular fashion in Fortran 2003
• Parallel execcution using MPI and OpenMP
• Data distribution over plane-waves, k-points, bands and property farms

Features