Resonant collisions of K Rydberg atoms.

Abstract

We have observed resonant-energy-transfer collisions between K Rydberg atoms. We have tuned the ${\mathrm{ns}}_{1/2}$+(n-2)${\mathrm{d}}_{\mathrm{j}}$\ensuremath{\rightarrow}${\mathrm{np}}_{\mathrm{j}\ensuremath{'}}$+(n-1)${\mathrm{p}}_{\mathrm{j}\mathrm{\ensuremath{''}}}$ collisional process into resonance with a static electric field. The measured resonance field positions from n=24 to 29 agree well with the calculated positions. We show that the dipole-dipole selection rule, \ensuremath{\Delta}${\mathrm{m}}_{\mathrm{j}}$=0,\ifmmode\pm\else\textpm\fi{}1, is valid for these resonances but that \ensuremath{\Delta}J=0,\ifmmode\pm\else\textpm\fi{}1 is not, due to the presence of the electric field. In addition, the polarization of the lasers used to excite the Rydberg states can suppress many of the resonances.