Collisional deactivation of vibrationally highly excited polyatomic molecules. II. Direct observations for excited toluene

Abstract

Vibrationally highly excited toluene molecules with 52 000 cm⁻¹ of vibrational energy have been prepared by UV laser excitation of the isomer cycloheptatriene and subsequent isomerization. The collisional loss of energy from the excited toluene molecules has been observed directly by monitoring hot UV absorption spectra. Direct measurements of the average energies 〈ΔE〉 transferred per collision have been made for about 60 different bath gases. For complex bath gases, 〈ΔE〉 values appear to be considerably smaller than those derived from earlier indirect measurements. 〈ΔE〉 was found not (or only slightly) to depend on the excitation energy.