Wikipedia
Q-Chem
Q-Chem is a general-purpose electronic structure package featuring a variety of established and new methods implemented using innovative algorithms that enable fast calculations of large systems on regular lab workstations using density functional and wave-function based approaches. It offers an integrated graphical interface and input generator, large selection of functionals and correlation methods including methods for electronically excited states and open-shell systems. In addition to serving the computational chemistry community, Q-Chem also provides a versatile code development platform.