# Chapter 14: One- and Two-Photon Electronic Spectroscopy

We now possess the tools t0 discuss one- and two-photon spectroscopies such as electronic absorption spectroscopy and resonance Raman spectroscopy. The basic formulas can be applied, with only minor modification, to a wide range of spectroscopies. For example, the basic one-photon formula can be used t0 describe electronic absorption, emission, photoionization, and photodetachment/ transition state spectroscopy. Similarly, the same basic two-photon formula describes resonance Raman scattering, two-photon absorption and dispersed fluorescence spectroscopy. The focus of this chapter will be on the formulation and the interpretation of this wide range of spectroscopies in terms of the Fourier transform of wavepacket time correlation functions.