Spectrally resolved three pulse photon echoes in the vibrational infrared

Spectrally resolved vibrational photon echo measurements of the N-3(-) ion in D2O and carbonmonoxy hemoglobin in D2O have been made using 100 fs infra red pulses in the 1800-2100 cm(-1) region. These measurements allow the sep aration of contributions from different Feynman pathways to the echo signal , allowing comparisons of the time dependence and correlation functions for the 1-0 and 2-1 coherence terms. The spectra show good agreement with a th eoretical description of the data fitted to previously determined multiexpo nential correlation functions. Fluctuations in the anharmonicity are found to be negligible for HbCO when the harmonic vibrational relaxation model is used. (C) 2000 Elsevier Science B.V. All rights reserved.