I've only a general grasp on how all this works, so it could be I'm asking this poorly or misunderstanding what happens. With that said:
The energy of EM radiation is a function of its frequency. With enough energy (a high enough frequency) I understand it's possible to knock an electron out of its orbit(al).
Let's say I had a neutral hunk of iron, and I want to try to knock out as many 3d6 electrons from it as I can. Beyond simply having a frequency with enough energy, would there be specific frequencies which were best able to knock out those electrons?
Or, asked differently, does anyone have a graph of the initial current produced when different frequencies of light hit some substance? If so, does it have local maxima and minima?