Electromagnetic radiation occurring in the Raman effect, which is of much lower intensity than the Rayleigh scattering in which the frequency of the radiation is higher than that of the incident light, i.e. displaced towards shorter wavelengths. If the frequency of the original light is ν, the frequency of the anti-Stokes radiation is ν+νk, where νk is the frequency of the rotation or vibration of the molecule. The spectral lines associated with anti-Stokes radiation are called anti-Stokes lines. The quantum theory of the Raman effect provides an explanation for the intensity of the anti-Stokes line being much less than the intensity of the Stokes line.