CARS-spectra of excited states of metalloporphyrins

It is shown that resonance coherent anti-Stokes Raman scattering (RCARS) spectra of Cu- and Ni-octaethylporphyrins contain lines corresponding to molecule vibrations both in the ground and excited electronic states. Mechanisms are given which lead to the appearance of vibrations in the excited state in RCARS spectra. The RCARS methods are shown to be promising for comparing molecule vibrations in different electronic states.