When in a molecular collision there is no transfer of energy among different degrees of freedom, there is said to be elastic scattering.
Sources:
PAC, 1982, 54, 1533. 'Glossary of terms used in nuclear analytical chemistry (Provisional)' on page 1540 (https://doi.org/10.1351/pac198254081533)
PAC, 1996, 68, 149. 'A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)' on page 163 (https://doi.org/10.1351/pac199668010149)