Lifetime of the First Excited Atomic States ofRb87

Abstract

The Hanle effect on the resonance lines of the ${\mathrm{Rb}}^{87}$ atom has been observed. The line shape of the signal for the $5{}_{}{}^2{}_{}{}^{}S_{\frac{1}{2}}^{}{}_{}{}^{}\leftrightarrow 5{}_{}{}^2{}_{}{}^{}P_{\frac{3}{2}}^{}{}_{}{}^{}$ is found to be Lorentzian, while that for the $5{}_{}{}^2{}_{}{}^{}S_{\frac{1}{2}}^{}{}_{}{}^{}\leftrightarrow 5{}_{}{}^2{}_{}{}^{}P_{\frac{1}{2}}^{}{}_{}{}^{}$ is dispersion-type. The half-width of these lines was observed to be 3.146±0.13 G and 23.0 G±5%, respectively. These values yield the lifetime of (2.71±0.14) ×${10}^{-8\mathrm{}}$sec and (3.0±0.3)×${10}^{-8\mathrm{}}$sec for the $5{}_{}{}^2{}_{}{}^{}P_{\frac{3}{2}}^{}{}_{}{}^{}$ and $5{}_{}{}^2{}_{}{}^{}P_{\frac{1}{2}}^{}{}_{}{}^{}$ states, respectively. The oscillator strengths for the corresponding transitions are found to be 0.673±0.03 and 0.32±0.03, respectively. When the temperature of the scattering cell was changed from 0 to 36°C, an apparent increase of the linewidth at higher temperature was observed. This effect has been explained as a magnetic-field-dependent radiative transfer effect at optical depth of the order of the scattering cell dimensions. When the data were analyzed with such an effect included, the reduced Hanle signal showed no temperature dependence of the half-width.