| Abstract
| - The optical rotations for six organic molecules (verbenone, fenchone, camphor, nopinone, Tröger's base,dimethyl-cyclopropane) and the transition metal complex [Co(en)3]3+ were calculated as a function ofwavelength using time-dependent density functional theory (TDDFT). In the calculations, a realistic behaviorof the optical rotation in the vicinity of an electronic transition was obtained by using a phenomenologicaldamping parameter of the order of 0.2 eV (0.007 au). In comparison with experiment, for the moleculesstudied here the sign and order of magnitude of the optical rotation as well as the excitation energies werereasonably well reproduced in most computations. These findings apply to the investigated wavelength rangestypically between about 200 and 650 nm even when using comparatively small basis sets. Such calculationsmight therefore routinely be applied to help assigning the absolute configurations of chiral molecules.Supplementary calculations of the circular dichroism (CD) and comparison with experimental CD were usedfor further assessment of the optical rotation calculations. In particular, a combined study of optical rotationand CD turned out to be useful in cases where the optical rotatory dispersion in a specific energy rangeexhibits a considerable blue or red shift or where it is difficult to reproduce because of an interplay of severalcompeting Cotton effects. The influence of basis set, density functional, and the damping parameter was alsoinvestigated.
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