energy gradient

https://dx.doi.org/10.1351/goldbook.ET07028
First derivatives of the total energy with respect to nuclear coordinates, i.e., negative values of forces on the nuclei. Evaluation of energy gradient plays a central role in searching potential energy surfaces for stationary points. A widespread technique is based on the minimization of the gradient norm (the square of energy gradient).
Source:
PAC, 1999, 71, 1919 (Glossary of terms used in theoretical organic chemistry) on page 1938