The relationship between the structure of an optically active molecule and the magnitude/direction of its induced rotation is undetermined despite years of active research. This issue is further exacerbated for solid crystals, for which experimental data is limited and few attempts at first principle calculation have been made. To investigate this phenomena, we have modeled the optical rotation of extended (but not periodic) helical structures of simple diatomic molecules. We find that the optical rotation plateaus with respect to the number of dimeric units that compose the helix. In order to investigate this effect, we use linear response calculations of the optical rotation to obtain orbital pair contributions in the configuration space of canonical and localized molecular orbitals of the helices. From these orbital contributions, we can make inferences regarding the effect of individual portions and the total length of the helix on the observed optical rotation. This insight could prove invaluable in predicting the optical activity caused by distinct structural moieties present in solids.

Optical rotation of diatomic, helical chains as a model for periodic systems

255th National Meeting (2018)

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