Sensitized fluorescence in caesium vapor.

D. A. McGillis

Published Jan 1, 1965• 0 citations

Abstract

Collisions of the second kind between caesium and caesium, caesium and helium, and caesium and xenon atoms, leading to P p the transfer of excitation between the 6 6 P^yg states in caesium, have been investigated by studying the sensitized fluorescence in caesium vapor at pressures in the range 2x10*^ • 7x10*5 mm Hg and in vapor-inert gas mixtures.These low caesium densities, at which trapping of resonance radiation is virtually absent, were previously Inaccesible to such measurements.The use of a high intensity light source and an improved fluorescence cell in conjunction with a very sensitive detection system, permitted accurate measurements of extremely low fluorescent intensities.The total collision cross sections for the processes ô^P^yg -> and 6 %]^yg<r-G^P^yg equal 0.64x10*^^ cm® and 3.1x10*15 ^^2 for caesium-caesium collisions, 0.41x10*®® cm® and 2.7x10*®® cm® for caesium-helium collisions, and 7 .6x10 *®! cm^ and 2.9x10*1^ cm® for caesium-xenon collisions respectively.The ratios of these cross sections agree well with the values predicted by the principle of detailed balancing except for the caesiumxenon collisions, where a shielding effect has been postulated to account for the discrepancy.ill

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