Independent Determination of Supercollision Energy Loss Magnitudes and Rates in Highly Vibrationally Excited Pyrazine with Evib = 36000−41000 cm-1

Abstract

We report results of the first state-resolved study of large ΔE energy transfer resulting from collisions of highly excited pyrazine with initial vibrational energies of 36000−41000 cm-1. We have used transient infrared absorption spectroscopy to monitor the rotational and translational energy gain in a CO2 bath at short times following collisions with highly excited pyrazine. We have measured nascent distributions of high-energy rotational states, J = 56−84, for CO2 in its ground vibrationless (0000) state, the translational energy gain associated with these excited rotational states, and state-resolved rate constants for excitation of the high-energy bath states. Our results show that for the CO2 rotational states investigated, the nascent rotational distributions and translational energies change very little for a 13% change in pyrazine energy. In contrast, the rate constants for these events are strongly influenced by the donor internal energy content and increase by an order of magnitude for a 5000 c...