Abstract
The theory of molecular excitation in beta decay is developed for the general case of a polyatomic molecule. Calculations of the daughter molecule vibrational excitation are carried through for diatomic molecules, and the results are presented graphically. Finally, the formation of the (He3H3)+ molecule ion in the decay of one nucleus of a tritium molecule is studied in detail. It is concluded that the (He3H3)+ ground electronic state vibrational spectrum should be observable in the light spontaneously emitted by tritium. For example, neglecting nonradiative transitions, one expects approximately 1014 photons per second to be radiated at wave number ≅2.35×103 cm1 by every gram of tritium in the 1→0 vibrational transition.