Say a hydrogen atom is accelerated so that both the nucleus and the bound electron gains kinetic energy exceeding it's electron binding energy, yes I know an hydrogen atom with 1 proton, 1 neutron and 1 electron is electrically neutral and therefore cannot be accelerated in an electric field. My question suppose it is possible for hydrogen atom to gain kinetic energy without absorbing photon, will the electron kicks itself out?

  • $\begingroup$ Are you asking what happens if the hydrogen atom is moving with some high velocity i.e. the average velocity of the proton and electron is the same? If so then obviously nothing happens because if you consider a stationary hydrogen atom there are reference frames in which the hydrogen atom isn't stationary and can have any velocity up to the speed of light. $\endgroup$ Oct 23, 2017 at 8:28
  • $\begingroup$ @JohnRennie: accelerated ion will emits photon so I was thinking maybe the electron could gain kinetic energy to get kick out instead of emitting photon. $\endgroup$
    – user6760
    Oct 23, 2017 at 8:50
  • $\begingroup$ If your concern is what happens during acceleration you should edit your question to make that more clear. $\endgroup$
    – garyp
    Oct 23, 2017 at 10:50

1 Answer 1


Imagine there is a suficiently extense and uniform gravitational field, so that each particle (electron, proton and neutron) can be accelerated with the same "force". Then consider the next two situations

  1. You drop the atom.

  2. You let the atom fixed and jump yourself down the gravitational field.

As far as the gravitational field remains uniform, I think that both situations are equivalent because each observer just sees the other accelerating and nothing more. In the second situation I would not expect the atom to change at all, thus neither in the first one.


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