The Imprisonment and Quenching of Sodium and Potassium Resonance Radiation.
G. H. Copley
The met h o d of delayed coincidences for measu r i n g lifetimes of excited states has been used to investigate imprisonment of radiation in potassium vapor and to measure quenching cross sections in mixtures of potassium w ith diatomic gases and sodium wi t h noble gases.The me thod has also been u s e d to investigate the possibility that a longlived molec u l a r complex might be formed in inelastic collisions between 2 potassium and xenon, which lead to excitation transfer between the P potassium states.The alkali metal atoms were excited w i t h short pulses of resonance radiation, and the delays between the exciting and fluores cent pulses were m e a s u r e d w i t h a time-to-amplitude converter.At 10 3 pure potassium densities below 10 atoms/cm , the m e a s u r e d lifetimes approach the constant values of 27.8 + 0 .8 and 27.6 + 0 .8 nsec, 2 2 corresponding to the m e a n lifetimes of the 4 ^^2 anc* ^ ^3 / 2 s t a t e s > respectively.At higher densities, the apparent lifetimes are in satisfactory agreement w i t h the predictions of H o l s t e i n 's theory.The decrease in the apparent lifetimes, u p o n addition of diatomic gases to the potassium vapor, yielded cross sections for quenching collisions w it h N^, H^, HD and D^, which equal 34.0 + 2 .0 X2, 9.4 + 1.3 X2, 11.9 + 1.5 X2 and 8 .0 + 2 .0 X2, respectively.Addition of the noble gases He, Ne, Kr, Ar and Xe to sodium vapor did not lead to any measurable change in the decay rates for the sodium states within the iii
•Jan 1, 1969•0 citations