The Kerr effect of amino acids in water

We report the Kerr effect of 18 L-a-amino acids in dilute aqueous solution. From these data and dielectric measurements reported in the literature we calculate the molar Kerr constants and dipole moments of the amino acids in water, using the Onsager model for a dielectric medium. We also deduce the components of the polarizability tensor along the dipole moment and the sum of the components normal to it. We apply the bond additivity approximation to deduce the conformations of the side chains of the aliphatic amino acids, phenylalanine and histidine. A simple model is presented that allows us to deduce the conformations of the side chains independent of any assumptions about the dielectric model and the optical anisotropy of the bonds of the side chains.