Classical mechanical photon echo of a solvated anharmonic vibration

The vibrational photon echo measurement employs short pulses of coherent infrared radiation to discriminate among line broadening processes of different time scales. The measurement has been analyzed with the optical Bloch equations, in which the coupling of a quantum three-level system to a bath is represented by dephasing times. A detailed treatment of vibrational dynamics in a molecular liquid requires a Hamiltonian model. As such models are more readily treated in classical than in quantum mechanics, we consider the calculation of the vibrational echo in classical mechanics. Vibrational echoes are calculated for a solvated anharmonic oscillator. The classical mechanical echo is shown to share attributes of a quantum mechanical calculation. (C) 2000 American Institute of Physics. [S0021-9606(00)50729-6].