Electrically tuned Förster resonances in collisions of NH3 with Rydberg He atoms

Abstract

Effects of weak electric fields on resonant energy transfer between NH3 in the X 1 A1 ground electronic state, and Rydberg He atoms in triplet states with principal quantum numbers n = 36 -41 have been studied in a crossed beam apparatus. For these values of n, electric-dipole transitions between the Rydberg states that evolve adiabatically to the |ns and |np states in zero electric field can be tuned into resonance with the ground-state inversion transitions in NH3 using electric fields, with energy transfer occurring via Förster resonance. In the experiments the Rydberg He atoms, traveling in pulsed supersonic beams, were prepared by resonant two-photon excitation from the metastable 1s2s 3 S1 level and crossed an effusive beam of NH3 before being detected by state-selective pulsed-electric-field ionization. The resonant-energy-transfer process was identified by monitoring changes in the ionization signal from the |ns and |np Rydberg states for each value of n. The electric field dependence of the experimental data is in good agreement with the results of calculations in which the resonant dipole-dipole coupling between the collision partners was accounted for.

Rydberg-state ionization dynamics and tunnel ionization rates in strong electric fields

“…In experiments in which ramped electric field ionization of the 37s state is implemented beginning in fields close to zero, the electric field switching rates are typically on the order of 200 V/cm/µs [7]. Consequently, under such conditions the turning point at the avoided crossing C2 at 192.8 V/cm may be considered the threshold adiabatic ionization field of the 37s state.…”

“…This work has been carried out in electric fields between 190 and 200 V/cm, which are in the vicinity of the classical adiabatic ionization electric field of the 1s37s 3 S 1 level at ∼ 197 V/cm. The Rydberg states investigated have been selected for study as they are of particular interest in the refinement and optimization of detection schemes used for studies of Förster resonance energy transfer in collisions with ground state ammonia molecules [7,8]. The experimental results have been compared with the results of calculations performed using semi-empirical analytical methods for the treatment of hydrogen-like Rydberg states with similar characteristics to those of the states investigated, and numerical methods based on the use of complex absorbing potentials (CAPs).…”

Microwave spectroscopy of the 1snp PJ3 fine structure of high Rydberg states in HeDeller1, Hogan2 2018Phys. Rev. ASelf Cite130100View full textAdd to dashboardCite

“…Our measurements of the Rydberg fine structure are of direct importance to hybrid cavity QED experiments involving helium atoms in triplet Rydberg states. They also provide important information which is required in the refinement of experiments to study resonant energy transfer in collisions of ammonia molecules with helium atoms in triplet Rydberg states [25].…”

Rydberg-State-Resolved Resonant Energy Transfer in Cold Electric-Field-Controlled Intrabeam Collisions of NH3 with Rydberg He Atoms

“…Resonant energy transfer in collisions between atoms in Rydberg states (Xe, Rb, and He) and polar ground-state molecules (NH 3 , HF, HCl, and CO) emanating from effusive sources operated at 300 K have been studied [6][7][8][9][10][11][12]. This work included, most recently, observations of electric-field-controlled energy transfer from the inversion sublevels in NH 3 to Rydberg states in He and Rb [13][14][15]. The formation of negative ions by electron transfer in collisions of atoms in Rydberg states with polar ground-state molecules, such as acetonitrile and cyclobutanone, at collision energies of ∼ 1 eV have also been investigated [16].…”