Table 1. List of the TR-SFG Experiments Discussed Here, the Data Obtained, and the Overall Significance of the Observations.

phenomenon	experiment	observation	relevance
intramolecular vibrational relaxation (IVR)	one-color pump–probe	bleach lifetime τ, reflecting vibrational relaxation (lifetime T1)	rate and mechanism of energy dissipation
IVR and reorientation	polarization controlled pump–probe	polarization-dependent bleach signal, reflecting anisotropy decay	rotational dynamics
spectral diffusion	two-color pump–probe and 2D SFG	time-dependent 2-D response reflecting frequency–frequency correlation function	structure fluctuations/structural reorganization
			intra/intermolecular coupling
			Förster energy transfer