MEASUREMENT OF THE RATIO OF THE CESIUM D-LINE TRANSITION STRENGTHS

High-precision laser absorption spectroscopy in a thermal vapor cell i s used in the measurement of the ratio of the D-line transition streng ths in the cesium atom. We find \[6p(2)P3/2\\(r) over right arrow\\6s( 2)S(1/2)]\(2)/ \[6p(2)P1/2\\(r) over right arrow\\6s(2)S(1/2)]\(2) = 1 .9809(9), which compares favorably with the ratio calculated from the most precise lifetime measurements of these states and the predictions of nb initio calculation. We also verify the predictions of impact-re gime line-broadening calculations for densities of order 10(18) atoms per m(3). Theoretical implications and future experimental promise are discussed. [S1050-2947(98)05008-2].