weak collision
A collision between two molecules in which the amount of energy transferred from one to the other is not large compared to Math - ei (Math - symbol is the Boltzmann constant and Math - symbol the absolute temperature).
See: strong collision
Source:
PAC, 1996, 68, 149 (A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)) on page 191