Collisional angular-momentum mixing of highly excitedNa(nD2)states byN2and CO

Cross sections for the collisional $l$ mixing of $\mathrm{Na}\left(n{}_{}{}^2{}_{}{}^{}D\right)$ states from $n=5\mathrm{} \mathrm{to} 14$ by ${\mathrm{N}}_2$ and CO have been measured by time-resolved laser fluorescence and calculated in a two-state approximation by assuming the perturbing gases are spherically symmetric. For both CO and ${\mathrm{N}}_2$ the experimental cross sections rise sharply from $n=5\mathrm{}$ to $n=10\mathrm{}$ and remain constant for $n>\mathrm{}10\mathrm{}$. The theoretical calculations overestimate the experimental cross sections by a factor of 3 from $n=10\mathrm{} \mathrm{to} 12$, but are in good agreement for the smaller $n$ values.