Search

A study was conducted to investigate the effect of alkylation on the strong collisional energy transfer between C[O.sub.2] and a series of highly vibrationally excited alkyl pyridines where alkyl = methyl, ethyl, and propyl. The results have shown that the alkylated donors have undergone strong collision with C[O.sub.2] via a less repulsive part of the intermolecular potential than does pyridine.

Classical trajectory calculations are performed to simulate state-resolved energy transfer experiments of highly vibrationally excited pyrazine and CO2, which are conducted using a high-resolution transient infrared absorption spectrometer. The goal is to use classical trajectories to simulate the supercollision energy transfer pathway wherein large amounts of energy are transferred in single collisions in order to compare with experimental results.

A new approach is described for measuring absolute rates for molecular collisions along with contributions of strong and weak collisions. The method is used for the collisional relaxation of highly vibrationally excited pyrazine with HOD and the observed collision rate is nearly twice the Lennard-Jones collision rate.

The state-resolved measurements are used for studying the weak and strong collisions between HOD and highly vibrationally excited pyrazine ([E.sub.vib] = 37 900 [cm.sup.-1]). The results have shown that water is an efficient quencher because of a large collisional energy transfer cross section and not due to a large supercollision tail.