Computing optical properties of conformationally flexible molecules

Filipp Furche, filipp.furche@chemie.uni-karlsruhe.de, Institut für Physikalische
Chemie, Universität Karlsruhe, Kaiserstr. 12, D- 76128 Karlsruhe, Germany

I will review recent extensions and improvements of the time-dependent density
functional (TDDF) treatment of optical and excited state properties. With the
advance of computational methods and technology, molecules can be treated under
increasingly realistic conditions, e.g., in solution and at finite
temperature. These effects are of special importance for optical rotatory
dispersion (ORD) and circular dichroism (CD) spectra of conformationally
flexible molecules, because small conformation changes can lead to radical
changes in the ORD and CD spectra. I will show that conformational flexibility
can be captured by combining TDDF calculations with ab initio molecular dynamics
simulations. Given a reasonably efficient (TD)DF code, medium-sized molecules
can be reliably treated by this method, as I will demonstrate for several
classes of beta-lactam antibiotics. Solvation effects are included by continuum
solvent models.