Collisional deactivation of higher Nasand manifold states byN2

The cross sections for deactivation of the Na $5s-9s$ and $n=5-8\mathrm{}$ manifold ($l\ge 2$) states by ${\mathrm{N}}_2$ have been measured using a laser-induced fluorescence approach. The cross sections are: $6s$, 84(8) ${\mathrm{\AA }}^2$; $7s$, 82(9) ${\mathrm{\AA }}^2$; $8s$, 91(8) ${\mathrm{\AA }}^2$; $9s$, 104(10) ${\mathrm{\AA }}^2$; five manifold, 43(7) ${\mathrm{\AA }}^2$; six manifold, 36(8) ${\mathrm{\AA }}^2$; seven manifold, 32(7) ${\mathrm{\AA }}^2$; and eight manifold, 18(6) ${\mathrm{\AA }}^2$. The $s$-state cross sections are in qualitative agreement with a curve-crossing model. The decrease of the manifold cross sections with $n$ is attributed to the increasing multiplicity of the manifold with $n$.