Q-Chem

 http://www.q-chem.com/

Q-Chem, Inc. based in Pleasanton California, USA, brings commercial, academic and government scientists worldwide in pharmaceuticals, materials science, biochemistry and other fields a comprehensive ab initio quantum chemistry program to solve computational problems faster, more accurately and less expensively than they could otherwise. Q-Chem also provides users with the highest level of technical support possible. The company was established in 1993.

Thousands of Q-Chem copies are being used around the world. About 55,000 licensed copies of Q-Chem have been sold up to date through Spartan alone. The citations of the two Q-Chem papers reached 300 per year in 2014, and is growing (as reported by ISI Web of Science).