Exploring Response Properties of Molecules and Extended Systems Using Theoretical Methods

With support from the Chemical Structure, Dynamics, and Mechanisms-A (CSDM-A) program of the Chemistry Division, Professor Jochen Autschbach of the University at Buffalo, State University of New York, will develop quantum theoretical methods and perform large-scale computer simulations, to learn how molecular structure, chemical bonding, and molecular motion determine a variety of molecular properties that can be measured in experiments. The project will advance the understanding of the relationships between molecular structure and measured properties of molecules. Furthermore, these studies will likely contribute to a better understanding of the interactions between light and matter. The project will provide training for graduate and undergraduate students and opportunities for summer internships of high school students, for example, in scientific computer programming. The project focuses on molecular properties that are of high practical value in informing about the structures and functions of molecules, and the dynamics of chemical systems. The theory developments and simulations will be crucial to establish and refine the sought-after structure-property relationships. The project will focus specifically on NMR relaxation phenomena, and on the structural and electronic origins of optical activity. In addition, the behavior of a special class of organic radicals will be studied by calculations, complemented by experiments performed by PI Autschbach’s collaborators. The radicals show an energetic inversion of the singly and the highest occupied molecular orbital, which has attracted much interest in materials science and related fields. Specifically, the investigation of radicals that display what the PI terms SOMO-HOMO inversion provides an interesting area of fundamental research; collaborations with synthetic chemists will allow for examination/validation of the computational predictions. Another important aspect of the planned studies relates to NMR relaxation. NMR relaxation contains a wealth of information about the dynamics and the characteristic dynamic time scales of a chemical system. Relaxation will be predicted by ab-initio and force-field molecular dynamics simulations. The optical activity-related part of the project will focus on resonance effects in Raman vibrational optical activity, circularly polarized luminescence, and magnetic-field induced optical activity. 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.