Long-range potentials for two-species alkali-metal atoms

Abstract

We address a growing interest in trapping and cooling of mixed-species alkali-metal atoms. Long-range coefficients that arise in the multipole expansion of molecular potentials for unlike alkali-metal dimers are calculated. The coefficients for the heteronuclear alkali-metal dimers corresponding to different molecular symmetries that separate to nS-nЈS,nS-nЈP,nS-nЈD, and nP-nЈP atomic levels are computed with high precision. We consider cases where in the infinite separation limit, one atom is in the ground state and the other is in one of the lowest S, P, and D excited states and both atoms are in their lowest excited P states. We find the long-range potentials for Rb(5S)-Cs(6S),Rb(6S)-Cs(6S),K(4S)-Rb(5 P) 1,3 ⌺,K(4P)-Cs(6 P) 1,3 ⌺, and Rb(5S)-Na(3D) 1,3 ⌺ molecules to be the most attractive. The K(4S)-Rb(5 P) dimer represents the best candidate molecule for ultracold photoassociative spectroscopy. We also find the K(4 P)-Cs(6 P) and Rb(5S)-K(4 P) dimers to form, respectively, the most attractive and the most repulsive long-range potentials. The present calculation is in good agreement with experimentally determined value for the 1/R 6 van der Waals coefficient for the interaction between Cs(6S) and Li(2 P) atoms. ͓S1050-2947͑99͒07101-2͔

XΣ+1andaΣ+Staanum1, Pashov2, Knöckel3 et al. 2007Phys. Rev. A1199592View full textAdd to dashboardCite

“…With the present data sets we are also able to reproduce the experimental data with the same quality of the fit by fixing these coefficients to the values from Ref. [39]. The reason for choosing the more recent values is that in this case the fitted C 10 coefficient differs from the theoretical prediction by only -17 %, whereas if the leading dispersion coefficients are fixed to the values from Ref.…”

“…The reason for choosing the more recent values is that in this case the fitted C 10 coefficient differs from the theoretical prediction by only -17 %, whereas if the leading dispersion coefficients are fixed to the values from Ref. [39] the difference reaches +68 % (the derived C 10 amounts in this case to 2.39 × 10 10 cm −1Å10 ). The selected set gives good consistency with the expected accuracy of most recent calculations of dispersion coefficients.…”

“…R o is chosen as described in Refs. [27,38], the C 6 and C 8 coefficients are fixed to their theoretical values [39,40,41], γ and β are estimated using the ionization potentials for Li and Cs [42] according to Ref. [37], while U ∞ , C 10 and A ex are adjusted during the fitting procedure.…”

Multichannel modeling and two-photon coherent transfer paths in NaK

“…This is given as an inverse power series involving the individual dispersion coefficients, where high quality theoretical values are tabulated in the literature [23,24]. The LeRoy radius for NaK is reported as 10.8Å [12], yet the only RKR curve fully covering the region until that value is the B 1 Π [12] one, thus it implies that one has to borrow an ab initio shape in order to bridge the part between RKR and long-range description.…”

“…to the potential energy curves (PECs) of the involved electronic states [9][10][11][12][13], and are supplemented by sophisticated theoretical studies of molecular properties like radiative lifetimes, dipole moments or static polarizabilities [14,15]. Recently, Feshbach resonances have been observed [16] and ultracold fermionic 23 Na 40 K Feshbach molecules created subsequently [17]. Yet the two-photon transfer of Feshbach molecules into rovibronic ground state molecules remains to be explored.…”