JEEP is a general purpose ab initio electronic structure program, with molecular dynamics capability. It is distributed freely. JEEP was written in C/C++ by François Gygi and currently runs on five different platforms, including vector supercomputers and small workstations. JEEP is based on Density Functional Theory, norm-conserving pseudopotentials, and plane-wave basis functions.

Some of JEEP's features include

• A new Tcl/Tk graphical user interface.
• The new Generalized Gradient Approximation of Perdew, Burke and Ernzerhof (PBE) for exchange and correlation.
• Constant volume molecular dynamics.
• Finite temperature simulations.
• An X Windows tool for 3D visualization of atoms, charge densities and orbitals.
• An X Windows tool and associated script files for the visualization of energies, atomic positions and forces, temperature, etc.. in the course of a simulation.
• Stress calculations and constant pressure molecular dynamics.

The purpose of the JEEP project is to give access to first principles molecular dynamics (MD) technology to non-specialists, who do not wish to become experts, nor have intimate knowledge of an ab initio MD program. JEEP should be well adapted to teaching the essentials of first principles MD. Yet, many of its features (like e.g. the possibility of using any pseudopotential in numerical form) make it a useful research tool.

JEEP was developed with emphasis on ease of use rather than optimal performance on a specific platform. It uses as little as possible the specific capabilities of a given platform. In spite of this, JEEP gives very competitive performance as compared to similar first-principles programs.