Probing electron correlations in molecules by two-dimensions coherent optical spectroscopy

The nonlinear optical signal generated in phenol by three femtosecond pulses with wavevectors [k.sub.1], [k.sub.2] and [k.sub.3] in the phase-matching direction [k.sub.1] + [k.sub.2] - [k.sub.3] is simulated. The signal has vanished for uncorrelated electrons due to interference among quantum pathways, which is illustrated by the very different two-dimensional coherent spectroscopy (2DCS) signals.