Spectroscopy of the double minimum 3 3ΠΩ electronic state of 39K85Rb

Abstract

We report the observation and analysis of the 3 (3)ΠΩ double-minimum electronic excited state of (39)K(85)Rb. The spin-orbit components (0(+), 0(-), 1, and 2) of this state are investigated based on potentials developed from the available ab initio potential curves. We have assigned the vibrational levels v' = 2-11 of the 3 (3)Π1,2 potentials and v' = 2-12 of the 3(3)Π0(+/-) potential. We compare our experimental observations of the 3 (3)ΠΩ state with predictions based on theoretical potentials. The observations are based on resonance enhanced multiphoton ionization of ultracold KRb in vibrational levels v" = 14-25 of the a (3)Σ(+) state. These a-state ultracold molecules are formed by photoassociation of ultracold (39)K and (85)Rb atoms to the 5(1) state of KRb followed by spontaneous emission to the a state.

Formation of ultracold 7Li85Rb molecules in the lowest triplet electronic state by photoassociation and their detection by ionization spectroscopy

“…This would explain qualitatively why deeper vibrational levels of the a 3  + state show more intense REMPI lines than is predicted from FCFs calculation. It is worth mentioning that similar disagreement between calculations and experiment has been observed in other REMPI spectra [26,28]. Revisiting the excited state PECs with the help of experimental data might help to improve theoretical calculations, which in turn may lead to a more accurate calculation of the FCFs.…”

“…We hope that our measurements will motivate development of an improved model for the 3 3  state. We note that degeneracy of the 0 + and 0 -components, as well as roughly equal spacing between  = 0 and 1, and  = 1 and 2 has also been observed in REMPI spectroscopy performed in KRb [28].…”

“…3b) and experiment has been observed in other REMPI spectra [26,28]. Revisiting the excited state PECs with the help of experimental data might help to improve theoretical calculations, which in turn may lead to a more accurate calculation of the FCFs.…”

Ab initio multi-reference perturbation theory calculations of the ground and low-lying electronic states of the KRb molecule

“…Low-lying KRb triplet terms have been investigated by Pashov et al [13] (1 3 R + ), Kobayashi et al [15] (1 3 G), Amiot [11] (2 3 R + ), Lee et al [12,17], Kim et al [23] (3 3 R + ), Banerjee et al [14] (2 3 R + , 1 1 G) and Kim et al [23] (2 3 G). Highly-excited states of the KRb molecule were studied in [8,12,21,23,25,27,29,43].…”

Long-range interactions between rubidium and potassium Rydberg atoms

“…The works mentioned here have all been with regard to homonuclear interactions; to the author's knowl-edge, Rydberg interactions between multiple species has not yet been considered. Fairly recently, photoassociation between different alkali species in the ground state ( 39 K 85 Rb) was achieved [25,26]. In principle, such techniques could be applied to Rydberg states of these atoms to probe resonance features; this paper aims to assist in such an effort.…”