The linearized ion Fokker–Planck equation is solved as an eigenvalue problem under the condition of collisionless electrons in the quasineutral limit (&fgr;=0) for ionization‐temperature ratios,ZTe/Ti=2, 4, and 8 for entropy waves and ionization‐temperature ratios,ZTe/Ti=4, 8, 16, 32, 48, 64, and 80 for ion‐acoustic waves. The perturbed ion distribution function for the ion‐acoustic and entropy waves is formed from a Legendre polynomial expansion of eigenvectors and can be used to calculate collisionally dependent macroscopic quantities in the plasma such as gamma (&Ggr;=Cp/Cv), the ratio of specific heats, and the ion thermal conductivity (&kgr;i).