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 and data handling.

Summary of Capabilities

  • Interfaces to a variety of QM and MM codes, including
  • The above codes can be used in hybrid QM/MM coupling using an additive scheme. 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