Lifetimes and Alignment Depolarization Cross Sections of the $\left(4\mathrm{}{p}^{5}5p\right){}_{}{}^1{}_{}{}^{}{D}^{\prime }_2^{}{}_{}{}^{}$ and ${}_{}{}^3{}_{}{}^{}D_3^{}{}_{}{}^{}$ Levels in Krypton

The radiative lifetimes and alignment depolarization cross sections due to collisions with ground-state atoms of the $\left(4\mathrm{}{p}^{5}5p\right){}_{}{}^1{}_{}{}^{}{D}^{\prime }_2^{}{}_{}{}^{}$ and ${}_{}{}^3{}_{}{}^{}D_3^{}{}_{}{}^{}$ levels in Kr have been measured by the Hanle-effect method. Our results are $\tau \left({}_{}{}^1{}_{}{}^{}D_2^{\prime }{}_{}{}^{}\right)=3.02\mathrm{}\left(31\right)\mathrm{}\times {10}^{-8\mathrm{}}$ sec, $\tau \left({}_{}{}^3{}_{}{}^{}D_3^{}{}_{}{}^{}\right)=2.81\mathrm{}\left(25\right)\mathrm{}\times {10}^{-8\mathrm{}}$ sec, ${\overline{\sigma }}_2\left({}_{}{}^1{}_{}{}^{}D_2^{\prime }{}_{}{}^{}\right)=4.49\mathrm{}\left(32\right)\mathrm{}\times {10}^{-14\mathrm{}}$ ${\mathrm{cm}}^2$, and ${\overline{\sigma }}_2\left({}_{}{}^3{}_{}{}^{}D_3^{}{}_{}{}^{}\right)=4.79\mathrm{}\left(27\right)\mathrm{}\times {10}^{-14\mathrm{}}$ ${\mathrm{cm}}^2$. The cross sections were measured at $T=292\mathrm{}\left(6\right)\mathrm{}$ °K.