Payware for ab initio quantum chemical calculation. This application performs high-speed quantum chemical calculation based on the density functional, Hartree-Fock theory, and MP2 theories. It can perform structure optimization, spectrum analysis, evaluation of acid dissociation constants, and so on. It can treat excited states by using TDDFT and CIS. Maestro, an application for visualization produced by the same developer, provides a useful interface for Jaguar.