Potassium ground state scattering parameters and Born-Oppenheimer potentials from molecular spectroscopy

Abstract

We present precision measurements with MHz uncertainty of the energy gap between asymptotic and well bound levels in the electronic ground state X ${}^1{\Sigma }_{\mathrm{g}}^{+}$ of the ${}^{39}$K${}_2$ molecule. The molecules are prepared in a highly collimated particle beam and are interrogated in a $\Lambda$-type excitation scheme of optical transitions to long range levels close to the asymptote of the ground state, using the electronically excited state A ${}^1{\Sigma }_{\mathrm{u}}^{+}$ as intermediate one. The transition frequencies are measured either by comparison with I${}_2$ lines or by absolute measurements using a fs-frequency comb. The determined level energies were used together with Feshbach resonances from cold collisions of ${}^{39}$K and ${}^{40}$K reported from other authors to fit new ground state potentials. Precise scattering lengths are determined and tests of the validity of the Born-Oppenheimer approximation for the description of cold collisions at this level of precision are performed.

14 pages, 4 figures, 8 tables

References in corpus (9)

• Exploring an ultracold Fermi-Fermi mixture: Interspecies Feshbach resonances and scattering properties of 6Li and 40K
• Observation of molecules produced from a Bose-Einstein condensate
• p-wave Feshbach molecules
• Feshbach resonances in ultracold K(39)
• Tuning of heteronuclear interactions in a quantum-degenerate Fermi-Bose mixture
• The coupling of the X${}^1{\Sigma }^{+}$ and a${}^3{\Sigma }^{+}$ states of KRb
• KRb Feshbach Resonances: Modeling the interatomic potential
• Spectroscopy of the a^3Σ_u^+ state and the coupling to the X^1Σ_g^+ state of K_2
• Study of the Born-Oppenheimer Approximation for Mass-Scaling of Cold Collision Properties

Cited by in corpus (2)

• Feshbach resonances in an ultracold ${}^7$Li and ${}^{87}$Rb mixture
• Direct evaporative cooling of 41K into a Bose-Einstein condensate