Nuclear wave function, geometric phase

The phase-change nale, also known as the Ben phase [101], the geometric phase effect [102,103] or the molecular Aharonov-Bohm effect [104-106], was used by several authors to verify that two near-by surfaces actually cross, and are not repelled apart. This point is of particular relevance for states of the same symmetry. The total electronic wave function and the total nuclear wave function of both the upper and the lower states change their phases upon being bansported in a closed loop around a point of conical intersection. Any one of them may be used in the search for degeneracies. 

As mentioned in the introduction, the simplest way of approximately accounting for the geometric or topological effects of a conical intersection incorporates a phase factor in the nuclear wave function. In this section, we shall consider some specific situations where this approach is used and furthermore give the vector potential that can be derived from the phase factor. 

III. NUCLEAR WAVE FUNCTIONS AND THE GEOMETRIC PHASE EFFECT FOR CONICAL INTERSECTIONS... 

Althorpe SC. General explanation of geometric phase effects in reactive systems Unwinding the nuclear wave function using simple topology. J Chem Phys. 2006 24 084105. 

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