The determination of cross-sections for the quenching of resonance radiation of metal atoms. IV. Results for lithium

The flame fluorescence technique has been used to study the fluorescence of lithium in sets of isothermal hydrogen-oxygen flames diluted with each of the gases argon, nitrogen and carbon dioxide. The measurements have given the following values (Å2) for the quenching cross-sections, σ2, of lithium in the 2p2P state: σ2H2= 5⋅2, σ2H2O ═ 1⋅9, σ2N2 ═ 6⋅75, σ2CO ═ 12⋅6, σ2CO2 ═ 9⋅2, σ2Ar ≼ 0⋅3. The cross-section is defined as the square of the distance between centres of colliding species. These values are compared with those previously reported (Jenkins 1966, 1968) for the other alkali metals and their interpretation discussed. Details of the high intensity hollow cathode lamp used as a source of lithium resonance radiation are also given.