Sum rules for the squared modulus of the nonlinear Raman susceptibility

Abstract
We construct new sum rules for the nonlinear susceptibility modulus of Raman processes using the complex analysis proposed in a previous paper [K.-E. Peiponen, Phys. Rev. B 37, 6463 (1988)]. The validity of the sum rules is confirmed by the Lorentzian line-shape approximation for the Raman susceptibility.