The technique of Doppler-free two-photon spectroscopy was used to measure rates for line broadenings and frequency shifts of Rydberg levels with pressure. Measurements were made of spectra of $^{2}\mathrm{S}$ and $^{2}\mathrm{D}$ states (with n\ensuremath{\sim}10--40) for ${\mathrm{Rb}}^{\mathrm{*}\mathrm{*}}$ +Rb and ${\mathrm{K}}^{\mathrm{*}\mathrm{*}}$ +K, and of $^{2}\mathrm{S}$ states (with n=14--29) for ${\mathrm{K}}^{\mathrm{*}\mathrm{*}}$ +Rb. Large oscillations are observed in both broadening and shift rates for n\ensuremath{\sim}20--30 in all series except for the $^{2}\mathrm{D}$ series in ${\mathrm{Rb}}^{\mathrm{*}\mathrm{*}}$ +Rb. Overall rates for broadening and shift are compared with a theory based on the ``free-electron'' model. The observed oscillations are inconsistent with theories based on the resonance scattering of the Rydberg electron by the perturbing atom. A possible alternative mechanism related to interference in l-mixing collisions is suggested.The technique of Doppler-free two-photon spectroscopy was used to measure rates for line broadenings and frequency shifts of Rydberg levels with pressure. Measurements were made of spectra of $^{2}\mathrm{S}$ and $^{2}\mathrm{D}$ states (with n\ensuremath{\sim}10--40) for ${\mathrm{Rb}}^{\mathrm{*}\mathrm{*}}$+Rb and ${\mathrm{K}}^{\mathrm{*}\mathrm{*}}$+K, and of $^{2}\mathrm{S}$ states (with n=14--29) for ${\mathrm{K}}^{\mathrm{*}\mathrm{*}}$+Rb. Large oscillations are observed in both broadening and shift rates for n\ensuremath{\sim}20--30 in all series except for the $^{2}\mathrm{D}$ series in ${\mathrm{Rb}}^{\mathrm{*}\mathrm{*}}$+Rb. Overall rates for broadening and shift are compared with a theory based on the ``free-electron'' model. The observed oscillations are inconsistent with theories based on the resonance scattering of the Rydberg electron by the perturbing atom. A possible alternative mechanism related to interference in l-mixing collisions is suggested.

Physical Review AJan 1, 198735 citations

Collisional broadening of Rydberg-atom transitions by ground-state alkali atoms

M. E. Henry, Roger M. Herman

A theory is developed that allows a qualitative explanation and quantitative calculation of the widths and shifts of the two-photon Doppler-free transitions from the ground states of alkali atoms to Rydberg n 2 S and n 2 D states. The widths and shifts result from collisions between Rydberg atoms and ground-state alkali atoms, either of the same or of other species. The collisions are represented by means of a pseudopotential that is a function of theoretically calculated free-electron elastic scattering resonant and nonresonant phase shifts, which depend upon the Rydberg electron momentum. The momentum, in turn, is correlated with the electronic position within the Rydberg atom. This theory assumes classical straight-line trajectories and takes into consideration the multicollisional nature of the Rydberg-electron-perturbing-atom interaction within the Rydberg atom. Impact theory calculations of the linewidths and shifts for K**( n S)-K, K**( n S)-Rb, Rb**( n S)-Rb, Rb**( n S)-K, K**( n D)-K, K**( n D)-Rb, Rb**( n D)-Rb and Rb**( n D)-K show substantial agreement with experiment for 10⩽ n ⩽40.A theory is developed that allows a qualitative explanation and quantitative calculation of the widths and shifts of the two-photon Doppler-free transitions from the ground states of alkali atoms to Rydberg n 2 S and n 2 D states. The widths and shifts result from collisions between Rydberg atoms and ground-state alkali atoms, either of the same or of other species. The collisions are represented by means of a pseudopotential that is a function of theoretically calculated free-electron elastic scattering resonant and nonresonant phase shifts, which depend upon the Rydberg electron momentum. The momentum, in turn, is correlated with the electronic position within the Rydberg atom. This theory assumes classical straight-line trajectories and takes into consideration the multicollisional nature of the Rydberg-electron-perturbing-atom interaction within the Rydberg atom. Impact theory calculations of the linewidths and shifts for K**( n S)-K, K**( n S)-Rb, Rb**( n S)-Rb, Rb**( n S)-K, K**( n D)-K, K**( n D)-Rb, Rb**( n D)-Rb and Rb**( n D)-K show substantial agreement with experiment for 10⩽ n ⩽40.

Journal of Physics B Atomic Molecular and Optical PhysicsJan 10, 20024 citations

Linear Stark effect for Rydberg atoms of alkali metals

Petr A. Braun

Optics and SpectroscopyAug 1, 19861 citation

Pressure Shift and Broadening of Alkali Rydberg States.

David Thompson

Jan 1, 19860 citations

The technique of Doppler-free two-photon spectroscopy was used to measure rates for line broadenings and frequency shifts of Rydberg levels with pressure. Measurements were made of spectra of

^{2}\mathrm{S}

and

^{2}\mathrm{D}

states (with n\ensuremath{\sim}10--40) for

{\mathrm{Rb}}^{\mathrm{*}\mathrm{*}}

+Rb and

{\mathrm{K}}^{\mathrm{*}\mathrm{*}}

+K, and of

^{2}\mathrm{S}

states (with n=14--29) for

{\mathrm{K}}^{\mathrm{*}\mathrm{*}}

+Rb. Large oscillations are observed in both broadening and shift rates for n\ensuremath{\sim}20--30 in all series except for the

^{2}\mathrm{D}

series in

{\mathrm{Rb}}^{\mathrm{*}\mathrm{*}}

+Rb. Overall rates for broadening and shift are compared with a theory based on the ``free-electron'' model. The observed oscillations are inconsistent with theories based on the resonance scattering of the Rydberg electron by the perturbing atom. A possible alternative mechanism related to interference in l-mixing collisions is suggested.