The collisional behaviour of Cl(3p5(2Psub(1/2)) by time-resolved attenuation of atomic resonance radiation in the vacuum ultraviolet

A study is presented of the collisional behaviour of chlorine atoms in the 2Psub(1/2) spin orbit state, 881 cm-1 above the 3Psub(3/2) level in the 3p5 ground state configuration. Cl(32Psub(1/2)) was generated by the repetitive, pulsed irradiation of CCl4 and monitored photoelectrically in absorption by time-resolved attenuation of atomic resonance radiation in the vacuum ultraviolet at lambda=136.34 nm [3p44s(2Psub(3/2))from3p5(2Psub(1/2)0)]. The method includes a sophisticated signal averaging system and will be of general applicability to the kinetic study of this important atomic state, one that is of considerable current interest but that has hitherto been the subject of very limited investigation by direct observation. Absolute rate constants (ksub(Q), cm3 molecule-1, s-1, 300 K) are reported for collisional quenching by the gases CCl4[2.0+-0.2)x10-10], Cl2[4.5+-0.4)x10-11], O2[(2.1+-0.5)x10-11] and He[(3.8+-0.6)x10-15]. (Auth.)