steric isotope effect
A @S05523@ attributed to the different vibrational amplitudes of @I03351@. For example, both the mean and mean-square amplitudes of vibrations associated with C–H bonds are greater than those of C–D bonds. The greater effective bulk of molecules containing the former may be manifested by a @S05997@ on a rate or @E02177@.
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1131 [Terms] [Paper]