1. The problem statement, all variables and given/known data Why don't hydrogen cross-sections exhibit resonances? 2. Relevant equations N/A 3. The attempt at a solution I was thinking it had something to do with the spin, the fact that is has only one electron, or elastic scattering, but I can't seem to wrap my brain around resonances enough to form any answer that makes real sense. If anyone can lead me in the right direction here that would be awesome- thanks!