Improved LeRoy–Bernstein near-dissociation expansion formula, and prospect for photoassociation spectroscopy

We have produced ultracold heteronuclear YbRb * molecules in a combined magneto-optical trap by photoassociation. The formation of electronically excited molecules close to the dissociation limit was observed by trap loss spectroscopy in mixtures of 87 Rb with 174 Yb and 176 Yb. The molecules could be prepared in a series of vibrational levels with resolved rotational structure, allowing for an experimental determination of the long-range potential in the electronically excited state.PACS numbers: 34.20.Cf, 37.10.Mn Ultracold polar molecules offer fascinating prospects for the realization of new forms of quantum matter [1] with possible applications to quantum information [2] and to precision measurements [3,4]. While dense atomic clouds are routinely laser-cooled to µK temperatures, the complex internal structure of molecules has so far prevented the successful application of this direct approach. Among the various approaches currently under investigation [5], the production of translationally cold molecules from mixed-species ensembles of ultracold atoms is one of the most promising. The possible routes for the conversion from atoms to molecules involve either the use of magnetically tunable Feshbach resonances [6] or lightassisted photoassociation [7].While Feshbach resonances allow for an efficient and well-controlled preparation of ultracold heteronuclear molecules in high vibrational levels of the electronic ground state, this method is not applicable to all atomic species. In particular, if one of the atomic species does not possess angular momentum in the ground state, experimentally acccessible Feshbach resonances are typically non-existent [6]. In contrast, production of ultracold molecules by photoassociation is in principle possible for all combinations of atomic species.So far all experimental investigations, which have produced ultracold heteronuclear molecules by photoassociation [8,9,10,11,12], including the very recent demonstration of optical trapping [13] and of state transfer of Feshbach molecules [14], have used mixtures of alkalis. In this Letter, we report on the controlled production of ultracold heteronuclear molecules in a mixture of the alkali rubidium (Rb) and the rare earth ytterbium (Yb) in an electronicallly excited state by single-photon photoassociation. While ultimately two or more light fields with different wavelengths will have to be used to produce ultracold ground state molecules [8,10], this is the first decisive step towards the production of a new class of dipolar molecules. The main difference between bialkalis and YbRb is that the ground state of bialkalis is always a 1 Σ 0 while in YbRb it is a 2 Σ 1/2 state. This implies that ground state YbRb molecules posess a significant magnetic dipole moment in addition to their electric dipole moment and can thus be trapped and manipulated using magnetic fields. An intriguing prospect for ultracold molecules with an unpaired electron such as YbRb is the realization of lattice spin models [15]. Our experiments were performe...

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“…3 illustrates, the observed line positions are reproduced by a fit to the theoretical model of Ref. [19]. The fit [22] Fig.…”

mentioning

confidence: 99%

“…The improved Leroy-Bernstein method as described in Ref. [19] has been used to assign vibrational quantum numbers and extract values for the dispersion coefficients. Since the total number of vibrational levels in the potential well is unknown, table I lists quantum numbers ∆ v ′ = v ′ − v ′ max relative to the last vibrationalelvel.…”

mentioning

confidence: 99%

Production of heteronuclear molecules in an electronically excited state by photoassociation in a mixture of ultracold Yb and Rb

et al. 2009

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“…[31], this term amounts for a noticeable fraction of about 11% of the van der Waals energy. However, a fitting using an im- proved LB formula [34] including both C 6 /R 6 and C 8 /R 8 contributions does not give satisfactory results as there are too many free parameters compared to the number of observed lines. We believe that scanning for deeper bound levels will not help to improve the results, as we are already close to the internuclear distance where exchange potential and higher order terms in the multipolar expansion should play a role.…”

Section: Long-range Fitting and Discussionmentioning

confidence: 99%

Long-range states of the NaRb molecule near theNa(3 2S1/2)+Rb(5
Zhu¹,
Li²,
He³
et al. 2016
Phys. Rev. A
11
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11
0
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We report a high-resolution spectroscopic investigation of the long-range states of the 23 Na 87 Rb molecule near its Na(3 2 S 1/2 )+Rb(5 2 P 3/2 ) asymptote. This study was performed with weakly bound ultracold molecules produced via magneto-association with an inter-species Feshbach resonance. We observed several regular vibrational series, which are assigned to the 5 attractive long-range states correlated with this asymptote. The vibrational levels of two of these states have sharp but complex structures due to hyperfine and Zeeman interactions. For the other states, we observed significant linewidth broadenings due to strong predissociation caused by spin-orbit couplings with states correlated to the lower Na(3 2 S 1/2 )+Rb(5 2 P 1/2 ) asymptote. The long-range C6 van der Waals coefficients extracted from our spectrum are in good agreement with theoretical values.

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“…To determine the density of states of the a 3 R + electronic potential, we use near dissociation expansion (NDE) theory [13,14]. For a potential of the form…”

Section: Bound-free and Bound-bound Calculationsmentioning

confidence: 99%

NaK bound–free and bound–bound 4 3Σ+→a 3Σ+ emission

McGeehan¹,

Ashman²,

Wolfe³

et al. 2011

Journal of Molecular Spectroscopy

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Improved LeRoy–Bernstein near-dissociation expansion formula, and prospect for photoassociation spectroscopy

Cited by 47 publications

References 68 publications

Production of heteronuclear molecules in an electronically excited state by photoassociation in a mixture of ultracold Yb and Rb

Production of heteronuclear molecules in an electronically excited state by photoassociation in a mixture of ultracold Yb and Rb

Long-range states of the NaRb molecule near theNa(3 2S1/2)+Rb(5
Zhu¹,
Li²,
He³
et al. 2016
Phys. Rev. A
11
0
11
0
View full text Add to dashboard Cite

NaK bound–free and bound–bound 4 3Σ+→a 3Σ+ emission

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Improved LeRoy–Bernstein near-dissociation expansion formula, and prospect for photoassociation spectroscopy

Cited by 47 publications

References 68 publications

Production of heteronuclear molecules in an electronically excited state by photoassociation in a mixture of ultracold Yb and Rb

Production of heteronuclear molecules in an electronically excited state by photoassociation in a mixture of ultracold Yb and Rb

Long-range states of the NaRb molecule near theNa(3 2S1/2)+Rb(5 Zhu1, Li2, He3 et al. 2016Phys. Rev. A110110View full textAdd to dashboardCite

NaK bound–free and bound–bound 4 3Σ+→a 3Σ+ emission

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Long-range states of the NaRb molecule near theNa(3 2S1/2)+Rb(5
Zhu¹,
Li²,
He³
et al. 2016
Phys. Rev. A
11
0
11
0
View full text Add to dashboard Cite