Mike
MC: Helium is *not* a catalyst, it happens to be a chemically inactive good heat transfer medium. He+ is a catalyst, ionized by electric fields in some experiments. The DSC is a sophisticated Calvet calorimeter system which does not ionize He. 'Chemically inactive' is FAR from a resistance to ionization. It is naive to think that He can remain non-ionized in the presence of a strongly ionic solute like NaH. The NaH provides the electric field. For instance, water is not strongly ionic but becomes easily ionized in proximity any weak acid of base. There is no reason to suggest that Helium, while it would be more resistant to transient ionization than water - can remain locally non-ionized when NaH is in proximity, which would have near-fields in excess of the 54.4 eV on a transient timescale. There is no doubt in my mind that He is an active catalyst in the situation mentioned, and I am pretty sure that Mills would not object to that characterization. Jones
