Professor Daniel Crawford
Department of Chemistry, Virginia Tech, USA
The optical properties of chiral molecules are among the most challenging to predict and simulate — even for state-of-the-art quantum chemical methods — because of their delicate dependence on a variety of intrinsic and extrinsic factors, including electron correlation, basis set, vibrational/temperature effects, etc. In numerous studies over the last decade, we have demonstrated the importance of advanced quantum chemical methods such as coupled cluster response theory for the prediction of an array of gas-phase chiroptical properties such as optical rotation angles, circular dichroism rotatory strengths, Raman optical activity scattering intensity differences, and more. The primary disadvantage of such methods, however, is their high-degree polynomial scaling, which limits significantly the size of systems to which they may be applied. Furthermore, solvation makes the task even more difficult, not only dramatically expanding the complexity of the simulation, but sometimes altering even the sign of the chiral response. It is thus essential that we reduce the computational demands of the more accurate and reliable quantum chemical methods. This lecture will explore the many ways in which we are pursuing both more efficient theoretical models of optical activity, but means for extracting deeper understanding from them.
"Reduced-Scaling Coupled Cluster Response Theory: Cahllenges and Opportunities", T. D. Crawford, A. Kumar, A. Bazanté, R. Di Remigio
WIREs Comput Mol Sci e1406,1-25 (2019). (doi:10.1002/wcms.1406)