Exploring Response Properties of Molecules and Extended Systems Using Theoretical Methods

With support from the Chemical Structure and Dynamics (CSD) program in the Division of Chemistry, Professor Jochen Autschbach of the University at Buffalo, State University of New York, is developing and applying quantum theoretical methods and computer simulations to investigate how the three-dimensional arrangement of atoms, their chemical bonding, and their motion in solutions determine a variety of properties of molecules and molecular assemblies. Properties that will be studied include nuclear magnetic resonance (NMR) parameters and natural optical activity, with potential applications in catalysis and in the design of new light-emitting materials.

The accurate prediction of these properties, and discerning their exact role in targeted applications remain a key challenge in computational chemistry. Professor Autschbach and his students will investigate the optical activity of novel helicene-based systems, open-shell states of organic molecules with unpaired electrons, including helicenes with radical substituents, and how dynamics in solutions influences NMR spin relaxation.

The project provides training for graduate and undergraduate students and create opportunities for summer internships of high-school students in scientific computer programming. Professor Autschbach will also create free-to-use educational scientific visualizations and open-source computational research tools.

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 driven by the underlying dynamics of molecules, and on the structural and electronic origins of optical activity.

In addition, the behavior of organic radicals with an unusual inversion of the highest occupied level of molecular orbitals and the energy of the singly occupied orbital will be studied by calculations, complemented by experiments that are being carried out in the laboratories of Professor Autschbach’s scientific collaborators. 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 focuses on circularly polarized luminescence, and on the properties of metal complexes with ligands that combine N-heterocyclic carbene (NHC) and helicene moieties.

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.