Quenching of excited ArI and H by H-2 in a gas discharge

The cross sections for quenching by H-2 Of the 4p'[1/2](1) and 4p'[1/2](0) states of Ar I, corresponding to emission lines at 696.5 and 750.4 nm, are obtained in a gas discharge using emission spectroscopy in conjunction with a laser-induced fluorescence measurement of the atomic hydrogen density, a nd found to be (1.3 +/- 0.3) x 10(-19) and (1.5 +/- 0.3) x 10(-19) m(2), re spectively. The cross sections for the quenching of H(n = 4) and H(n = 5) b y H-2 are obtained using emission spectroscopy and the known quenching cros s section for H(n = 3) and are found to be 3.1 (+/-0.1)(-0.9)x 10(-19) and 8.3 (+/-0.7)(-2.5) x 10(-19) m2,respectively, where the first uncertainty i s the random error and the second uncertainty is a possible systematic erro r.