Structural Chemistry by Fluctuation Measurement Using Inelastic Scattering

Abstract

Scattering is one of the most important techniques for the research of structural chemistry. Scattering is classified into three categories; elastic, inelastic, and quasi-elastic. Quesi-elastic scattering is a technique to measure the fluctuation of the target as the energy broadening of scattered waves. Quesi-elastic light scattering, which is called dynamic light scattering, is used for the estimation of the diffusion constant of the polymer and colloidal particles in solution. A drawback of dynamic light scattering is the lack of molecular selectivity since the scattered light used for dynamic light scattering is Rayleigh scattering. This account describes how to achieve molecular-selective dynamic light scattering. The basic idea is the use of inelastic (Raman) scattering instead of elastic (Rayleigh) scattering. It is derived that the fluctuation of the scattered light intensity is not observed from Raman scattering and phase-matching coherent Anti-Stokes Raman scattering (CARS) but from phase-mismatching CARS, which is named as dynamic Raman scattering. A proof-of-principle experiment of dynamic Raman scattering is also introduced.