Spectroscopic characterization of singlet-triplet doorway states of aluminum monofluoride

Abstract

Aluminum monofluoride (AlF) possesses highly favorable properties for laser cooling, both via the A${}^1\Pi$ and a${}^3\Pi$ states. Determining efficient pathways between the singlet and the triplet manifold of electronic states will be advantageous for future experiments at ultralow temperatures. The lowest rotational levels of the A${}^1\Pi ,v=6$ and b${}^3{\Sigma }^{+},v=5$ states of AlF are nearly iso-energetic and interact via spin-orbit coupling. These levels thus have a strongly mixed spin-character and provide a singlet-triplet doorway. We here present a hyperfine resolved spectroscopic study of the A${}^1\Pi ,v=6$ // b${}^3{\Sigma }^{+},v=5$ perturbed system in a jet-cooled, pulsed molecular beam. From a fit to the observed energies of the hyperfine levels, the fine and hyperfine structure parameters of the coupled states, their relative energies as well as the spin-orbit interaction parameter are determined. The standard deviation of the fit is about 15 MHz. We experimentally determine the radiative lifetimes of selected hyperfine levels by time-delayed ionization, Lamb dip spectroscopy and accurate measurements of the transition lineshapes. The measured lifetimes range between 2 ns and 200 ns, determined by the degree of singlet-triplet mixing for each level.

12 pages, 11 figures

References in corpus (3)

• Optical cycling of AlF molecules
• Characterisation of the $b^3{\Sigma }^{+},v=0$ State and Its Interaction with the $A^1\Pi$ State in Aluminium Monofluoride
• Spectroscopic characterization of the a${}^3\Pi$ state of aluminum monofluoride

Cited by in corpus (2)

• Small but large: Single organic molecules as hybrid platforms for quantum technologies
• Spectroscopic characterization of the a${}^3\Pi$ state of aluminum monofluoride