The Absorption of Light by Thallium Vapour on the Short Wave-Length Side of the Series Limit

G. V. Marr
1954 Proceedings of the Royal Society A  
Measurements of the absorption o f light in thallium vapour from the series lim it at 2030 to 1450 A are described. The absorption cross-section at the series lim it is 4-5 ± 0 -8 x 10~18cm2 and the /-num ber for the continuum over the range o f the experiment is 0-025 + 0-005. Auto-ionization lines are observed at 2007, 1610 and 1490A in agreement w ith those reported by Beutler & Demeter (19346). The moderately sharp line at 2007 A (2P° -* 4P j) has an /-num ber o f 0-005 ±0-001 and a
more » ... 0-001 and a lifetime o f 18 + 5 x 10-18s, while the broad line at 1610 A (*P® -> *£> §) has an /-number o f 0-52 + 0-09 and a lifetime o f 2-2+ 0-1 x 10-ls s. The 1490 A line (*P® *Pj) is sharp and the /-num ber is estimated to be of the same order as that of the line 2007 A. These results are discussed in relation to the auto-ionization selection rules and previous experimental and theoretical work is reviewed.
doi:10.1098/rspa.1954.0142 fatcat:2d5oqmhjivdppoy45qhdyu74ba