Mechanochemistry studies the coupling of mechanical and chemical phenomena on a molecular scale. It reveals the relation between external forces and molecular properties or chemical reactivity.

Q-Chem enables modeling molecular electronic structure under external pressures. Three theoretical models are available: Hydrostatic Compression Force Field (HCFF), extended Hydrostatic Compression Force Field (X-HCFF), and Gaussians On Surface Tesserae Simulate HYdrostatic Pressure (GOSTSHYP). They are available in geometry optimization and AIMD calculations.

The quantum mechanochemistry methods can find applications in single-molecule force spectroscopy (SMFS), sonochemistry (chemistry caused by ultrasound), nanoparticle synthesis and molecular machine design.