Electromagnetic effects adiabatic

The term a, therefore plays the role of a vector potential in electromagnetic theory, with a particularly close connection with the Aharonov-Bohra effect, associated with adiabatic motion of a charged quantal system around a magnetic... 

This clearly demonstrates that the effect of the conical intersection is to add a vector potential, analogous to the vector potential A in semiclassical electromagnetic theory, to the nuclear Schrodinger equation in the adiabatic limit. Calculations based on Eq. (11) have recently been reported [39, 42, 43]. 

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