Short-range photoassociation from the inner wall of the lowest triplet potential of ${}^{85}$Rb${}_2$

Abstract

Ultracold photoassociation is typically performed at large internuclear separations, where the scattering wavefunction amplitude is large and Franck-Condon overlap is maximized. Recently, work by this group and others on alkali-metal diatomics has shown that photoassociation can efficiently form molecules at short internuclear distance in both homonuclear and heteronuclear dimers. We propose that this short-range photoassociation is due to excitation near the wavefunction amplitude maximum at the inner wall of the lowest triplet potential. We show that Franck-Condon factors from the highest-energy bound state can almost precisely reproduce Franck-Condon factors from a low-energy scattering state, and that both calculations match experimental data from the near-zero positive-energy scattering state with reasonable accuracy. We also show that the corresponding photoassociation from the inner wall of the ground-state singlet potential at much shorter internuclear distance is weaker and undetectable under our current experimental conditions. We predict from Franck-Condon factors that the strongest of these weaker short-range photoassociation transitions are one order of magnitude below our current sensitivity.

7 pages, 3 figures; Accepted for publication in J. Phys. B

References in corpus (7)

• Hyperfine, rotational, and vibrational structure of the triplet ground state of Rb molecules
• Giant formation rates of ultracold molecules via Feshbach Optimized Photoassociation
• Enhancement of Ultracold Molecule Formation Using Shaped Nanosecond Frequency Chirps
• Enhancement of the formation of ultracold ${}^{85}$Rb${}_2$ molecules due to resonant coupling
• Efficient Formation of Ultracold Molecules with Chirped Nanosecond Pulses
• Observation of Deeply-Bound ${}^{85}$Rb${}_2$ Vibrational Levels Using Feshbach Optimized Photoassociation
• Observation and Analysis of Resonant Coupling Between Near-Degenerate Levels of the 2 1Σg+ and 1 1 Πg States of Ultracold 85Rb2

Cited by in corpus (2)

• Short-range Photoassociation of LiRb
• High-Resolution Spectroscopy of {R}ydberg Molecular States of ${}^{85}${R}b${}_2$ Near the $5s+7p$ Asymptote