The energy difference between `` classical '' carbocations and `` non-classical '' isomers is often very small , and in general there is little , if any , activation energy involved in the transition between `` classical '' and `` non-classical '' structures .
The energy difference between `` classical '' carbocations and `` non-classical '' isomers is often very small , and there is generally little , if any activation energy involved in the transition between `` classical '' and `` non-classical '' structures .