A couple of observations. If you are worried about the mechanical resonance of this reaction, don't use an engine with a crankshaft. Instead, just have a spring loaded piston with an adjustable tension to match the resonance of the reaction. Energy could then be extracted by electromagnetic means.
The Papp engine, though, seems to have relied on the UV triggered reaction between gaseous hydrogen and chlorine. The participation of the noble gases may have been the formation of numerous excimers with the chlorine. Maybe Papp didn't really know, assuming he wasn't a total fraud, which of these noble gasses was reacting, so he just more or less threw in the the kitchen sink. Or maybe he was so secretive he was trying to hide which gas did the trick. The UV triggered reaction between hydrogen and chlorine might OU itself. When I was a very mischievous boy, I used to make what I called sunlight bombs by filling glass bottles with a hydrogen and chlorine mixture. Hydrogen was made by electrolysis. Chlorine was generated by mixing Clorox and Sani-Flush which used to be sodium bisulfate. I put one of these outside at night expecting that the rising sun would set it off. It didn't happen. I discovered by further reading that the UV exposure had to be sudden. So with my next attempt I covered the bottle with a can attached to a string. When yanking the can off the bottle there would be an unexpectedly huge explosion. This observation, made more than 60 years ago, is purely subjective; but I can only say that the explosion was a lot bigger than the chemical reaction warranted. I am lucky that I escaped childhood with all my fingers and both eyes. On Saturday, June 13, 2020, 06:30:40 PM UTC, Jones Beene <jone...@pacbell.net> wrote: An interesting proposition for an advanced transportation fuel would be presented to us - IF (big if) hydrogen can be routinely converted into a denser form on a catalyst, and then expanded in a piston engine configuration. This concept would relate to using argon as a "pseudo oxidizer." Argon is not exactly "inert" to the same extent as helium and other Column eight atoms (Vlll on the periodic table). AFAIK this exact concept, when transposed into a piston engine configuration, has never been explored... or has it? There is the Papp engine, which used argon and other inert gases but did not use hydrogen; and there is the Laumann engine which included oxygen with argon and no surface catalyst -- but neither of those is precisely the same. According to Wiki, "argonium" is the name for argon hydride which is a (1+) ion species formed by combining a proton with argon into a short-lived molecule (2+ millisecond) life - which has a surprising strong binding energy. Argonium is actually found to be relatively common in interstellar space, despite this short lifetime. In a piston engine a short lifetime could actually be put to good use if an asymmetry exists due to the Mills effect. It would act as a thermal sink. Imagine a closed cycle piston engine which recirculates the two gases H2 ans Ar in such a way that under compression (at TDC) the two are combined on a catalyst surface (such as nickel, palladium, iridium etc) allowing for net energy to be freed as UV photons, which gain would be the result of some combination of the ion binding energy along with a redundant orbital photon emission less the ionization loss - as described by Mills, Holmlid etc. In Mills theory this emission would be related minimally to multiples of 27.2 eV so even if the reaction goes no further that a single redundant hydrogen orbital reduction, an attractive scenario for net gain would exist - even if the protons are lost after a single pass and must be continually replace by electrolysis of water.
