<b>CM THEORY SEMINAR</b><Br>Topological Effects in Molecular Dynamics Beyond the Born-Oppenheimer Approximation

The Born-Oppenheimer approximation for the electron-nuclear wave-function introduces natural separation between time scales of electrons and nuclei in molecular and condensed matter systems. This separation allows one to consider nuclear chemical dynamics independently from that of the electronic subsystem. However, there are also a few complications associated with cases when several electronic potential energy surfaces become similar in energy or even cross. The latter case often presents itself in the form of conical intersections (see the figure). For example, in many photochemical, charge and electronic energy transfer processes nuclear molecular dynamics proceeds near conical intersections. In this talk, I will discuss how non-trivial topological phases associated with conical intersections of electronic surfaces affect chemical dynamics of molecular systems and what intuitive picture can be extracted from exact numerical simulations for simple models.