LIFETIME MEASUREMENTS IN EXCITED S STATES OF K, RB, AND CS BY CASCADE HANLE EFFECT

The cascade Hanle-effect technique in fluorescence experiments is described in detail and is used to measure radiative lifetimes of the second excited S states of potassium, rubidium, and cesium, and of the third excited S state of cesium. Lifetime data in nanoseconds are tau (K, 6 **2S//1/////2) equals 68 plus or minus 9, tau (Rb, 7 **2S//1/////2) equals 91 plus or minus 11, tau (Cs, 8 **2S//1/////2) equals 96 plus or minus 14, and tau (Cs, 9 **2S//1/////2) equals 231 plus or minus 35.