Q-Chem is a comprehensive ab initio quantum chemistry package for accurate predictions of molecular structures, reactivities, and vibrational, electronic and NMR spectra. The new release of Q-Chem 4.0 represents the state-of-the-art of methodology from the highest performance DFT/HF calculations to high level post-HF correlation methods:

• Dispersion-corrected and double hybrid DFT functionals;
• Faster algorithms for DFT, HF and coupled-cluster calculations;
• Structures and vibrations of excited states with TD-DFT;
• Methods for mapping complicated potential energy surfaces;
• Efficient valence space models for strong correlation;
• More choices for excited states, solvation and charge-transfer;
• Effective Fragment Potential and QM/MM for large systems;
• Shared-memory for multicores and implementations for GPU's.
• For a complete list of new features, click here.

Q-Chem is available stand-alone here and as the fully integrated back-end of Spartan.