Hi,
I am trying to figure out how to apply boundary conditions in case of mixed isotopologues. If we have H2 and HT in gas, each with own partial pressure - is there a way to apply boundary conditions to find H and T concentrations under the surface of metal? As far as I remember, concentration of T should be proportional to P(HT), not square root. I could not find this in readthedocs, but this might be the usual case of me missing something. 
Best wishes,
Mikhail