Quenching of fluorescence from Na(3(2)P) and K(4(2)P) atoms following photodissociation of NaCl and KCl at 193 nm

Quenching of fluorescence from Na(3(2)P) and K(4(2)P) atoms by various collision partners was studied at 973 and 1273 K. Excited alkali atoms were produced photolytically by excimer laser light at 193 nm. For each collision pair, the appropriate relative velocity was computed and used to evaluate the quenching cross-section from the measured rate constants. Cross sections for CO2, O-2 and N-2, are large (10-60 Angstrom(2)) while for Ar, the values are <1 Angstrom(2). The results are compared with those of previous investigations as a function of relative velocity. Finally, implications for combustion diagnostics are briefly discussed.