The capability of electronic structure to calculate the wavefunctions, and even dynamics of large systems has improved dramatically. This has put electronic structure into an uncomfortable regime where statistical effects become as important as the correlation problem. I will discuss our efforts to describe mixed-state electronic dynamics with density matrix equations of motion, and the applications of those theories to ultrafast experiments. Statistical sampling of molecular geometries has become an equally important issue, although empirical density functionals, which are the most practical tools for exploring geometries, make an ambiguous mixture of quantum physics and statistical modeling. I will demonstrate purely statistical models of molecular structure, and show that in the near future it is likely that purely empirical models of the PES will have several appealing advantages over hybrids of quantum mechanical models with statistics.

Quantum mechanical models with statistical effects and statistical models without quantum effects

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.