We report experimental rate coefficients for the reverse heteronuclear energy-pooling collisions $\mathrm{K}(5D)+\mathrm{Na}(3S)\ensuremath{\rightarrow}\mathrm{K}(4P)+\mathrm{Na}(3P)$ and $\mathrm{K}(7S)+\mathrm{Na}(3S)\ensuremath{\rightarrow}\mathrm{K}(4P)+\mathrm{Na}(3P)$ at thermal energies. Both reactions are exothermic and very high rates were observed showing that reverse exothermic energy-pooling is an order of magnitude more efficient than the corresponding forward endothermic energy-pooling reactions. This is in accordance with the general behavior of the exothermic and endothermic energy-pooling rate coefficients in alkali-metal atoms. In the experiment the potassium atoms were excited in two steps to either the $5D$ or $7S$ state via the $4P$ level using two broadband cw dye lasers. A double-modulation technique has been used to select the fluorescence contributions at the $\mathrm{Na}{(3P}_{J})$ exit channels due only to the above reactions. The ground-state sodium and potassium atom densities were measured by the absorption of lines from a K-Na hollow-cathode lamp. The measured densities and fluorescence intensities have been used to obtain absolute reverse energy-pooling rate coefficients. The contribution to the rate coefficients from other processes are discussed.We report experimental rate coefficients for the reverse heteronuclear energy-pooling collisions $\mathrm{K}(5D)+\mathrm{Na}(3S)\ensuremath{\rightarrow}\mathrm{K}(4P)+\mathrm{Na}(3P)$ and $\mathrm{K}(7S)+\mathrm{Na}(3S)\ensuremath{\rightarrow}\mathrm{K}(4P)+\mathrm{Na}(3P)$ at thermal energies. Both reactions are exothermic and very high rates were observed showing that reverse exothermic energy-pooling is an order of magnitude more efficient than the corresponding forward endothermic energy-pooling reactions. This is in accordance with the general behavior of the exothermic and endothermic energy-pooling rate coefficients in alkali-metal atoms. In the experiment the potassium atoms were excited in two steps to either the $5D$ or $7S$ state via the $4P$ level using two broadband cw dye lasers. A double-modulation technique has been used to select the fluorescence contributions at the $\mathrm{Na}{(3P}_{J})$ exit channels due only to the above reactions. The ground-state sodium and potassium atom densities were measured by the absorption of lines from a K-Na hollow-cathode lamp. The measured densities and fluorescence intensities have been used to obtain absolute reverse energy-pooling rate coefficients. The contribution to the rate coefficients from other processes are discussed.

Physical Review AJan 1, 19988 citations

[Energy pooling collisions between excited Na and K atoms].

Yifan Shen, Wei Li

Two different atomic species, sodium and potassium, are resonantly excited in a ceel by a CW dye laser and a potassium lamp, respectively. The density of the excited Na (3P) atoms in the cell is measured directly using the absorption-equivalent-width technique on the lines of the diffuse series. To isolate the heteronuclear contribution in the fluorescence spectrum, a modulation detection technique is adopted. The energy-pooling collisions between Na (3P) and K (4P) are observed and cross sections are obtained.Two different atomic species, sodium and potassium, are resonantly excited in a ceel by a CW dye laser and a potassium lamp, respectively. The density of the excited Na (3P) atoms in the cell is measured directly using the absorption-equivalent-width technique on the lines of the diffuse series. To isolate the heteronuclear contribution in the fluorescence spectrum, a modulation detection technique is adopted. The energy-pooling collisions between Na (3P) and K (4P) are observed and cross sections are obtained.

Feb 1, 19970 citations

LASER-INDUCED COLLISIONAL THREE-PHOTON IONIZATION IN A POTASSIUM-SODIUM MIXTURE

Sun Tao-Heng, Qin Liu

Jul 18, 19880 citations

5D

7S

state via the

4P

level using two broadband cw dye lasers. A double-modulation technique has been used to select the fluorescence contributions at the

\mathrm{Na}{(3P}_{J})

exit channels due only to the above reactions. The ground-state sodium and potassium atom densities were measured by the absorption of lines from a K-Na hollow-cathode lamp. The measured densities and fluorescence intensities have been used to obtain absolute reverse energy-pooling rate coefficients. The contribution to the rate coefficients from other processes are discussed.