RADIATIVE LIFETIMES OF S-STATE AND D-STATE OF POTASSIUM

The radiative lifetimes of the 7s-11s and 5d-9d states of potassium have been measured by means of a time- and wavelength-resolved laser-induced- fluorescence approach. The observed lifetimes (in μsec), measured at a temperature of 355 K, of the 7s-11s states are 0.165(12), 0.260(14), 0.441(38), 0.60(13), and 0.91(12). The observed lifetimes (in μsec) of the 5d-9d states are 0.61(9), 0.89(6), 1.21(10), 1.59(13), and 2.04(30). The measured s-state lifetimes are roughly a factor of 2 shorter than the hydrogenic ones, and the measured d-state lifetimes are roughly a factor of 10 longer than the hydrogenic ones. The d-state lifetimes are reduced from the 0-K radiative lifetimes by as much as 20% by stimulated emission and absorption induced by blackbody radiation. For both s and d states the calculated and observed values of 355-K lifetimes agree to within 10%. © 1979 The American Physical Society.