Bart Kahr (NYU) Chiroptical Activity of Molecular Knots
Computed Gyration Tensors of Knotted Chiral and Achiral Topological Stereoisomers of C60 Cyclocarbons
Afton Gustafson, Sophia Sburlati, and Bart Kahr
Abstract: The electronic origins of the computed optical rotations of the simplest chiral and achiral chemical knots with comparatively simple compositions and large, anticipated magnetoelectric polarizabilities are provided. Linear response theory is used to calculate the gyration at 1064 nm of two knotted polyyne chains, topological stereoisomers of cyclo[60]carbon. One isomer is analogous to the trefoil knot with approximate D3 symmetry and the other the figure eight knot with approximate S4 symmetry. The response in each case can be attributed largely to a degenerate E excited state. An oriented achiral figure eight knot is considerably more optically active in some directions, than the chiral knot in any direction.