Horace,
* This makes no sense to me Jones. Mass Spectrometers work on ionized species. There would thus have to exist a reduced energy orbital for a D2+ dideuterino species. Further, even if such a species exists, to the degree no He is present, no mass 4 He++ species will show up in the mass spectrograph. OK - does it makes more sense to suggest the ionization potential at 54.4 eV can be identical for both species in many cases? Jones