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Physical Review A

Collisional energy transfer between excited-state strontium and noble-gas atoms

Debra Miller, L. You, J. Cooper, Alan C. Gallagher

Published Aug 1, 1992• 22 citations
Publisher

Abstract

Inert-gas-induced collisional transfer between the first four excited states of Sr has been measured by determining excited-state densities following pulsed laser excitation of the 5 $^{1}$P state. We observe 5 $^{1}$P collisional transfer exclusively to the 4 $^{3}$D state, with (\ensuremath{\sim}800 K) rate coefficients ranging from 0.24 to 2.0\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}11}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$ for the various gases. We also measure 4 $^{1}$${\mathit{D}}_{2}$ transfer primarily to the 4 $^{3}$D state, with rate coefficients of 0.65 to 6.8\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}11}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$. The 4 $^{3}$D state radiative lifetime is observed to be 2.9\ifmmode\pm\else\textpm\fi{}0.2 \ensuremath{\mu}s, collisional mixing between the 4 $^{3}$${\mathit{D}}_{\mathit{j}}$ fine-structure levels is essentially gas kinetic (k\ensuremath{\sim}5\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}10}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$), and k${10}^{\mathrm{\ensuremath{-}}13}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$ for 4 $^{3}$D\ensuremath{\rightarrow}5 $^{3}$P collisional transfer.

DOI
10.1103/physreva.46.1303

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Cross sections for $7^{2}D_{\frac{3}{2}}\ensuremath{\leftrightarrow}7^{2}D_{\frac{5}{2}}$ transfer in Rb, induced in collisions with He, Ne, Ar, and with ground-state Rb atoms, have been determined using methods of atomic fluorescence. Rb vapor, pure or mixed with a noble gas, was irradiated in a glass fluorescence cell with pulses of 660-nm radiation from a N2{\mathrm{N}}_{2}N2​-laser-pumped dye laser, populating one of the 2D^{2}D2D states by two-photon absorption. The resulting fluorescence included a direct component emitted in the decay of the optically excited state and a sensitized component arising from the collisionally populated state. Relative intensities of the components yielded the cross sections for 72D7^{2}D72D mixing: $Q(^{2}D_{\frac{3}{2}}\ensuremath{\rightarrow}^{2}D_{\frac{5}{2}})=8.8,6.5,10.4, \mathrm{and} 30$; $Q(^{2}D_{\frac{3}{2}}\ensuremath{\leftarrow}^{2}D_{\frac{5}{2}})=5.8,4.0,6.9, \mathrm{and} 18$, in units of ${10}^{\ensuremath{-}14}$ cm2{\mathrm{cm}}^{2}cm2 for He, Ne, Ar, and Rb, respectively. Cross sections for the effective quenching of the 2D^{2}D2D states were also determined.
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