Welcome to ChemShell

ChemShell is a scriptable computational chemistry environment for multiscale modelling. While it supports standard quantum chemical or force field calculations, its main strength lies in hybrid QM/MM calculations. The concept is to leave the time-consuming energy evaluation to external specialised codes, while ChemShell takes over the communication, data handling and higher level tasks such as geometry optimisation and molecular dynamics.

Summary of Capabilities

• Interfaces to a variety of QM and MM codes, including GAMESS-UK, NWChem, FHI-aims, DALTON, Orca, MNDO, TURBOMOLE, Molpro, Gaussian,
  DMol3, Q-Chem, DL_POLY, GULP, CHARMM, and GROMOS.
• Hybrid QM/MM coupling using additive or subtractive schemes. The coupling models implemented in ChemShell include:
  • Mechanical Embedding
  • Electrostatic Embedding
  • Solid-state embedding scheme using shell model potentials (GAMESS-UK/NWChem + GULP)
• A range of geometry optimisers for finding minima and transition states, including a linear-scaling delocalised coordinate algorithm
• MD driver, incorporating NVE, NVT, NPT, and MC integration, rigid body motion (quaternions), distance and other constraints (SHAKE)
• Utilities:
  
  • Internal coordinate definition and manipulation
  • Mapping of potential energy surfaces
  • Finite difference vibrational frequencies
  • Restraints for umbrella sampling and complex potential energy surface scans
  • Evaluation of ESP and RESP charges from some QM codes that do not support this

Please see the news page for the latest ChemShell developments and highlights of research using ChemShell.