Collisional deactivation of vibrationally highly excited polyatomic molecules. III. Direct observations for substituted cycloheptatrienes

Abstract

Vibrationally highly excited ethyl-cycloheptatriene (41 600 cm−1) and isopropyl-cycloheptatriene (41 800 cm−1) molecules in the electronic ground state have been prepared by UV laser excitation inducing one-photon absorption and subsequent internal conversion. Collisional energy loss of these molecules has been followed directly by hot UV absorption spectroscopy. Average energies transferred per collision 〈ΔE〉 have been determined for a series of bath gases. 〈ΔE〉 values were found, for a given bath gas, to increase very slightly with the size of the excited molecule.