Reply to comment on ‘Multiple quantum coherences in liquid state NMR and nonlinear optics; collective vs. local origin’ [Chem. Phys. Lett. 357 (2002) 327]

The close analogy between the multiple quantum resonances observed in NMR and many-body effects in time and frequency domain nonlinear optical spectroscopy is explained. The nonlinear exciton Equations provide a systematic hierarchial method for incorporating and classifying collective effects beyond the mean-field level. The apparent inconsistencies pointed out by Jeener are caused by terminology differences which are clarified.