If you take nothing else from Mukamel, learn the diagrams. These are the "Practical Approach" to keeping track of the math. Each diagram tells a story:
Most practical nonlinear experiments (photon echoes, transient gratings, 2D spectroscopy) rely on three distinct laser pulses. Why three? Because two wouldn't be enough to separate "blurring" from "moving." If you take nothing else from Mukamel, learn the diagrams
Mukamel does almost everything in . Standard quantum mechanics uses vectors ($|\psi\rangle$) to describe states. Liouville space uses density matrices ($\rho$) to describe populations and coherences. If you take nothing else from Mukamel, learn the diagrams
Identify the specific experiment you want to model (e.g., 2D IR). If you take nothing else from Mukamel, learn the diagrams