Polarized Raman optical activity in methyl antisymmetric deformations: influence of heteroatom Rydberg orbitals

Abstract

Large deviations from the factor of 2 in the ratio of polarized to depolarized Raman optical activity intensities in methyl antisymmetric deformations in 1-phenylethanol and 1-phenylethylthiol are reported. It is suggested that these deviations might originate in large electric quadrupole contributions induced by excited-state interactions involving heteroatom Rydberg p orbitals and orbitals on other parts of the molecule. Such interactions appear to undermine the bond polarizability theory of Raman intensities