Photon-Atom Interaction: Atomic Spectrum vs Photoelectric Effect

Question

Apologize if the question is elementary or already asked (not aware of it).

Far as I understand:

• Ground state electrons in atom can only absorb photons of certain (discrete set of) energies to jump to higher energy levels;
• In photoelectric effect there is a threshold $E_0$ such that photons of energy greater than $E_0$ can eject electrons from metal atoms.

Is the following understanding correct?

1. Low energy photons interact with atoms only if they have energy equal to difference of electron energy levels (to bring an electron to excitation);
2. High energy photons can always interact with atoms, e.g. eject the electron(s).

Answer 1

you state:

Ground state electrons in atom can only absorb photons of certain (discrete set of) energies to jump to higher energy levels;

The correct statement is "atoms can absorb photons of certain (discrete set of) energies to jump to higher energy levels;"

The electrons with the nucleus are one quantum entity ,the atom.

your 1. correct, the electrons change energy levels with the correct photon energy input.

your 2. The energy levels close to ionisation are very dense, see for the hydrogen atom. It will depend on the particulars of the interaction. In general part (equal to the difference in the energy level of the electron to the ionization level) of the photon energy can go to releasing an electron.

On a conducting solid surface the binding of the electrons is with the whole lattice, and this is the effect seen in the photoelectric effect, depending on the atoms that make the solid.