Temperature dependence of blackbody-radiation-induced transfer among highly excited states of sodium

The rate of blackbody-radiation-induced transfer from the $19s$ state of sodium to the $18p$ and $19p$ states has been measured over the temperature range 6 to 210 K. The rate, which ranges from 2 × ${10}^3$ to 20 × ${10}^3$ ${\mathrm{s}}^{-1\mathrm{}}$, is sensitive to several transfer coefficients and spontaneous transition rates as well as to the precise form of the radiative distribution. The results are in good agreement with theory.