A chem major would be more inclined to give you a correct answer. Excited means to put electrons at a higher orbital, ionization basically means to get rid of electrons.
It's on my physics homework, ergo I aminclined to ask a physicsfag u_u anywho, Makaze told me anywya so.. Thanks makmak <3
Ooh I know this one ^,^ but Machina beat me to it. Excitation is where an electron moves to a higher orbital and ionisation is when the atom loses the electron completely.
Positrons of course. Unfortunately, side effects include total destruction of the electron and positron, so they're not exactly used.
Spoiler [video=youtube;rlNw5ZuDYsk]http://www.youtube.com/watch?v=rlNw5ZuDYsk&list=FLxgZhI7Dj67aVricfhnseWQ&index=30&feature=plpp_video[/video]