# Photoelectric effect and energy levels

The photoelectric effect is defined to strip electrons from a surface by high-frequency photons, independent of the intensity of the photons. However, each atom has electron orbitals that represent different energy levels that the electron has to go through until the electron goes to a high enough energy level that it would break through the EM force attracting the electron to the nucleus(unless enough time elapses that the electron will go to a lower energy state and emit a photon for each energy level.) I also get that the photoelectric effects works based on the work function which depends on the ionization energy of the material chosen for the electrons to bounce off. So my question is that, does the photoelectric effect work for only valence electrons? If not, why doesn't the element selected turn into plasma? Would the material chosen all be positive ions once all electrons possible have been bounced off the selected material? If I chose an element like lithium or beryllium, why would a high-frequency photon be required for a low-energy state?

The photoelectric effect was observed in metals.

In the main model for solids , the band theory,

In metals the conduction band is not empty, which means there are electrons not bound to a particular atom but to the lattice as a whole, with so dense energy levels to be considered continuous. It is those electrons that are ejected by interacting with a photon in the photoelectric effect.

With this in mind:

does the photoelectric effect work for only valence electrons?

Not on valence electrons but electrons in the conduction band

If not, why doesn't the element selected turn into plasma?

It needs a lot of energy to make a plasma and the photons used are of low ev energy

Would the material chosen all be positive ions once all electrons possible have been bounced off the selected material?

The piece of metal would be positively charged

If I chose an element like lithium or beryllium, why would a high-frequency photon be required for a low-energy state?

Maybe this publication will answer this question for lithium.

It is possible that the conduction band of metals that show little photoelectric effect have special properties due to their atomic structure or lattice structure.

So my question is that, does the photoelectric effect work for only valence electrons?

Impacting photon energy goes like this : $$h\nu = E_{_{ionization}} + \frac {mv^2}{2}$$ Ionization energy depends on exact energy level where electrons occur, in what shells, etc. So the answer is that in general photoelectric effect applies to all electrons, simply there's biggest chances that photon will knock-out electrons from outer shells, because these have lowest ionization energies, thus has lower thresholds for photon frequency.

why doesn't the element selected turn into plasma?

If light has required high frequency for passing ionization threshold and comes in high intensity, then yes - material is converted into plasma. That's how Laser cutting works.