Joseph Subotnik of the University of Pennsylvania is supported by an award from the Theory, Models and Computational Methods program in the Chemistry division to develop new computational and theoretical techniques for uncovering when and how molecules change spin state and potentially emit light in the form of phosphorescence (which is commonly observed). Subotnik is also exploring how the presence of a metal surface affects changes in spin state. The software tools developed by this proposal are being released on the PI's github page and in modern electronic structure packages, e.g. Q-Chem. The outreach activities of this proposal include an annual conference in theoretical chemistry (the Penn Conference in Theoretical Chemistry) which is very inexpensive for the public (and often free) and which also offers exceptional graduate students and postdocs the chance to speak.
In more detail, Subotnik and his research group are developing computational tools in both electronic structure and dynamics for quantifying spin crossovers, so that one can monitor the flow of energy and population in the condensed phase. On the electronic structure side, they are calculating energies, gradients and derivative couplings that are consistent with most nonadiabatic dynamics algorithms. On the dynamics side, Subotnik and coworkers are formulating a theory of the electronic friction tensor at a metal surface that is consistent with spin-orbit coupling, so that the effects of spin changes near a metal surface can be estimated and the branching of triplet states can be quantified. The Subotnik group is also investigating how spin effects enter into semiclassical electrodynamics, beyond mean-field theory.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
