Rydberg-Stark deceleration of atoms and molecules

The large electric dipole moments associated with highly excited Rydberg states of atoms and molecules make gas-phase samples in these states very well suited to deceleration and trapping using inhomogeneous electric fields. The methods of Rydberg-Stark deceleration with which this can be achieved are reviewed here. Using these techniques, the longitudinal motion of beams of atoms and molecules moving at speeds as high as 2500~m/s have been manipulated, with changes in kinetic energy of up to $|\Delta E_{\mathrm{kin}}|=1.3\times10^{-20}$~J ($|\Delta E_{\mathrm{kin}}|/e=80$~meV or $|\Delta E_{\mathrm{kin}}|/hc=650$~cm$^{-1}$) achieved, while decelerated and trapped samples with number densities of $10^6$--$10^7$~cm$^{-3}$ and translational temperatures of $\sim150$~mK have been prepared. Applications of these samples in areas of research at the interface between physics and physical chemistry are discussed.