Magnitude of Zero-Point Vibrational Corrections to Optical Rotation in Rigid Organic Molecules:  A Time-Dependent Density Functional Study

The zero-point vibrational corrections (ZPVCs) to the optical rotation of 22 rigid organic molecules have been calculated using time-dependent density functional theory with the B3LYP hybrid functional. We outline an implementation for calculating ZPVCs that can be applied with a variety of quantum chemistry programs and methods. It is shown that the ZPVCs to optical rotation have a wide range of values and can be quite significant depending on the molecule. On average, it has been determined that vibrational corrections can account for about 20% of the optical rotation for the equilibrium value. It is also concluded that vibrational effects alone cannot be the only factor in improving the calculated values of optical rotation with respect to experimental data measured in solution.