Automated high-resolution CARS spectrometer and coherent spectroscopy of the Raman scattering by tetrahedral molecules

A description is given of a spectrometer for coherent anti-Stokes Raman scattering (CARS) with an instrumental resolution of $\thicksim10^{-3}$ cm${}^{-1}$ and an automated data acquisition and processing system. The results are given of CARS investigations of the rotational structure of the vibrational state $\nu_1(a_1)$ of the sphencal-top molecules $CH_4$ and $CD_4$.