Bond polarizability and vibronic coupling theories of Raman optical activity: The electric-dipole magnetic-dipole optical activity tensor

Abstract

A new formulation of the bond polarizability and vibronic coupling theories of Raman optical activity (ROA) is presented in which terms dependent upon the nuclear momentum are introduced for the first time. The new terms appear in the magnetic-dipole electric-dipole optical activity tensor and are directly analogous to the non-Born–Oppenheimer, momentum-dependent terms required in the formulation of the theory of vibrational circular dichroism. Through the use of simplifying approximations in the ROA vibronic coupling theory, a term-for-term correspondence with the bond polarizability theory is established. It is shown that the new terms are smaller than the original terms by the ratio of the vibrational transition frequency to the frequency of the incident radiation. The new terms also contribute oppositely to Stokes and anti-Stokes ROA which provides a basis for their experimental isolation.