Computational Photochemistry: Onwards with first-principles
Shane Parker, Department of Chemistry, Case Western Reserve University
Photochemistry lies at the heart of chemical, biological, and technological processes, from photosynthesis to solar electricity generation. To harness the potential of light to drive new chemistry, a detailed understanding of the mechanisms of photochemical reactions is necessary. However, this is difficult to impossible to achieve based on experimental observations alone (often spectroscopy). I will introduce nonadiabatic molecular dynamics (NAMD) simulations using time-dependent density functional theory (TDDFT), an increasingly important framework that can unravel the atomistic details of photochemical reactivities. In particular, I will discuss two examples to showcase the power of NAMD-TDDFT. In the first example, I will present the first fully unconstrained simulations of UV-induced water splitting on titanium dioxide nanoparticles with which we uncover a rapid electron-proton transfer mechanism. In the second example, I will discuss the photodeactivation of gas-phase thymine for which NAMD-TDDFT predictions reproduce experimental time scales in better agreement than all prior state-of-the art methodologies at a fraction of the computational cost. The excellent cost-to-performance ratio of NAMD-TDDFT make it a powerful tool for photochemical mechanism discovery and with recent developments, it is poised to become routine.
Host: Walter Lambrecht