Time: May.31, 2023  15：30

Address：Room 314

DFT is currently the most widely used quantum chemistry method, for which Walter Kohn was awarded the 1998 Nobel Prize in Chemistry. However, it is a theory only for one state. I will introduce the density functional theory of excited states, extending Hohenberg-Kohn theorems for the ground state to any number of N-lowest eigenstates. We proved a one-to-one relationship between the Hamiltonian and the multistate matrix density D(r), In other words, the Hamiltonian is a matrix functiona of D(r). Furthermore, variational minimization of the trace of the Hamiltonian yields the exact energies and densities of all N eigenstates. Importantly, a minimum active space (MAS) consisting of no more than N² determinants is sufficient to represent D(r). I will present the method of multistate density functional theory (MSDFT), its implementation in the Qbics program, and its applications to energy decomposition analysis of excited states and an energy dissipation process in photosynthesis.