Vibrational-exciton relaxation probed by three-pulse echoes in polypeptides Original Research Article

Infrared photon echoes are simulated for an anharmonic vibrational dimer representing a dipeptide in the amide I spectral region by solving the nonlinear exciton equations for the vibrational-exciton model. New relaxation-induced resonances are predicted. Variations of the cross-peak intensities during the middle time interval show signatures of exciton population transfer and coherence dynamics. Enhanced resolution is achieved using phase sensitive detection.