Effects of ion and electron correlations on neutrino scattering in the   infall phase of a supernova
  Many authors have used one-component plasma simulations in discussing the role of ion-ion correlations in reducing neutrino opacities during the collapse phase of a supernova. In a multicomponent plasma in which constituent ions have even a small range of N/Z ratios neutrino opacities are much larger, in some regions of parameters, than for the case of a one component plasma. 
R. F. Sawyer