Localized MO analysis of the 1,2-hydrogen shift mechanism

For the 1.2-hydrogen shift, a localized SCF MO analysis shows that two different electronic rearrangement mechanisms are possible. In the first case, the migrating hydrogen behaves as a hydride along the entire reaction path; in the other case. the migrating hydrogen first behaves as a hydride, but in the second half of the reaction behaves as a naked proton. The difference between the two mechanisms appears to be related to the spatial orientation of the lone-pair orbitals.