Intramolecular energy transfer between mixed molecular states - Observation of interference effect and determination of phase angle

A distinct collisional quantum interference effect has been observed in col lision-induced intramolecular energy transfer between mired states of CO(A( 1) Pi, e(3) Sigma(-)) for the first time by using optical-optical double re sonance multiphoton ionization technique. A simple, explicit expression for the cross-section of mixed state energy transfer is derived, which embodie s an interference term. An interference phase angle, theta(ST) is defined t o measure the coherence between singlet-singlet and triplet-triplet energy transfer channels. theta(ST), for various collision partners is measured un der different temperatures, providing the dynamic information for different collision interactions.