[SOLVED] self diffusion of water Hi, I was wondering if anyone could give me a hand- or point in the right direction about a question I have concerning the self diffusion coefficients of HDO vs H2O18. To calculate the effective diffusion coefficients of isotopes of water in groundwater most people use the self-diffusion coefficients in Wang, Robinson and Edelman 1952 in which H2O18>HDO and HTO. I've found more recent references but they compare the diffusion coefficients of D2O and H2O18- I can't seem to find any mention of HDO. So, I guess my questions is; would you expect H2O18 to diffuse faster than HDO? Thanks!