Collisional excitation of CO2(0000) vibrationless state by the highly translationally excited HCN produced from the photodissociation of s-triazine

The collisional excitation of CO2(0000) state by quenching of highly translationally excited HCN has been studied with high-resolution diode laser absorption spectroscopy. The translationally hot HCN is produced from the photodissociation of s-triazine (1,3,5-triazine) at 266 nm. The average translational energy of HCN is measured to be 18±1 kcal/mol, which corresponds to 84% of available energy for the HCN fragment. The fraction of available energy partitioned into the rotational excitation is 15%. A little excitation in the HCN bending vibration is observed. The nascent rotational excitation in the 0000 levels of CO2, due to collisions with the translationally hot HCN (from s-triazine), is accompanied by a substantial enhancement in the translational energy. The excitation in the translational recoil velocities appears to increase with increasing J in 0000 vibrational state.