SEARCH Articles Figures Tables Atom-photon interaction Atomic Particles, Photons and the Quantization of Electron Energies Heisenbergs Uncertainty Principle Atomic systems photon correlations Atoms photon cross sections Light, Photon Energies, and Atomic Spectra Photon flux Photonic atoms Photon-atom interaction and photoionization matrix elements Skill 17. 3 Analyzing the relationships among electron energy levels, photons, and atomic spectra Two-photon quasi-resonant atomic processes