Spherical boundary potential for MD simulations in water. The interface implements only the mechanical component of the potential of Beglov & Roux[1] which uses adaptive sphere radius to maintain a constant pressure of 1 atmosphere. The electrostatic interaction of the solvent with the cavity is not calculated, nor is the angular correction described in the paper. Even this partial implementation yields results sufficient for use. The electrostatics can be covered by using a suitable implicit solvent model in the underlying calculation