Quantum Mechanical Photochemistry

We are working on several aspects of the general problem of quantum mechanical calculations of photochemistry. This includes more accurate methods for calculating electronic excitation energies by Kohn-Sham density functional theory and by multi-configuration pair-density functional theory, new ways to treat conical intersections, new methods for diabatization, and simulations of molecular photodissociation processes by coherent switches with decay of mixing and army ants tunneling. Selected highlights of recent progress will be presented in the lecture. I am grateful to several collaborators who will be acknowledged in the lecture.