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Drag C Laburthe Tolra B T'Jampens B Comparat D Allegrini M Crubellier A Pillet P 《Physical review letters》2000,85(7):1408-1411
In photoassociation spectroscopy, the line intensities of a given vibrational progression exhibit zero-signal modulation reflecting the node structure of the s-wave ground state wave function of two free colliding atoms. This leads to the determination of the scattering length. We performed photoassociation of cold Cs atoms polarized in the Zeeman sublevel f = 4, m(f) = 4. We analyzed the intensities of the lines associated with the Cs2 0(-)(g) state dissociating to the 6s(1/2)+6p(3/2) asymptote. This yields a value of the Cs triplet state scattering length, a(T) = -530a(0), while consistency requirements impose a value of the multipole ground state molecular coefficient, C6 = 6510 a.u. 相似文献
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Q. Beaufils A. Crubellier T. Zanon B. Laburthe-Tolra é. Maréchal L. Vernac O. Gorceix 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,56(1):99-104
We develop a theoretical model to describe the
radio-frequency (rf) induced coupling of a pair of colliding atoms
to a Feshbach molecule when a magnetic field arbitrarily far from
the Feshbach resonance is modulated in time. We use the dressed atom
picture, and show that the coupling strength in presence of rf is
equal to the Feshbach coupling strength multiplied by the square of
a Bessel function. The argument of this function is equal to the
ratio of the atomic rf Rabi frequency to the rf frequency. We
experimentally demonstrate this law by measuring the rate of
rf-association of molecules using a Feshbach resonance in d wave
collisions between ultra-cold chromium atoms. 相似文献
3.
D. Comparat C. Drag B. Laburthe Tolra A. Fioretti P. Pillet A. Crubellier O. Dulieu F. Masnou-Seeuws 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,11(1):59-71
We report on the formation of translationally cold Cs2 ground state molecules through photoassociation in the 1u attractive molecular state below the 6
s
1/2
+6
p
3/2
dissociation limit. The cold molecules are obtained after spontaneous decay of photoassociated molecules in a MOT and in
a dark SPOT. We also used polarized atoms, in the f
=3, m
f
=+3Zeeman ground state. Purely asymptotic and adiabatic calculations including hyperfine interaction and rotation are in excellent
agreement with observed structures. As expected, the 1u state is actually a pure long-range state, consisting of paired atoms, uniquely linked by the first terms of the multipole
expansion of the electrostatic interaction. A temperature of 20 K has been measured for the molecular cloud.
Received 19 July 1999 相似文献
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N.?Vanhaecke Ch.?Lisdat B.?T’Jampens D.?Comparat A.?Crubellier P.?PilletEmail author 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2004,28(3):351-360
Over 100 high lying level energies of the lowest electronic states
and
in Cs2 are determined in a
-like scheme two-colour photoassociation spectroscopy. The results are analyzed with a coupled channel model using an asymptotic approach, based on nodal lines. From this analysis we determine the long range dispersion coefficient C6 to 6846.2
15.6 a.u. We also obtain the first experimental determination of the amplitude of the asymptotic exchange term.Received: 4 November 2003, Published online: 20 January 2004PACS:
34.20.-b Interatomic and intermolecular potentials and forces, potential energy surfaces for collisions - 32.80.Pj Optical cooling of atoms; trapping - 03.65.Ge Solutions of wave equations: bound states 相似文献
6.
We present a simple quantum-mechanical treatment of the cooperative interaction between an ensemble of two-level atoms initially in their ground state and the electromagnetic field inside a Fabry-Perot cavity, in the weak field limit. In this limit the atoms have to be considered as being collectively dressed by the field and important cooperative effects are expected in the transient regime. It is shown that, in a first approximation, the evolution of the atom-field system in the general case can be deduced from the very simple “one-excitation” problem. A Rabi nutation at a frequency which depends essentially on the number of atoms is predicted. At resonance, these oscillations are closely related to superradiance “ringing” oscillations and have been observed very recently. 相似文献
7.
A. Crubellier O. Dulieu F. Masnou-Seeuws M. Elbs H. Knöckel E. Tiemann 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,6(2):211-220
A simple model is developed to determine a scattering length from the experimental values of the energy of the last, least bound, vibrational levels of the ground state, either 1Sg+^1\Sigma _g^{+} or 3Su+^3\Sigma _u^{+},of an alkali dimer. It is based on an extrapolation of the positions of the few outermost nodes of the bound vibrational wave functions towards the dissociation threshold. It uses the asymptotic part of the molecular potential only. The method is applied to recently measured levels at the asymptote (3s+3s) of Na2. We obtain precise values for the two scattering lengths respectively associated to the dissociation limits F1=F2=1,F=2 (55.1±\pm 1.6 a0) and F1=F2=1,F=0 (50.0±\pm 1.6 a0); the first value corresponds to the a1,-1 scattering length usually considered in cold collisions. The extrapolation procedure is also applied to Li2, using existing experimental data. 相似文献
8.
A. Fioretti E. Arimondo A. Crubellier 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,12(2):219-225
The measurements of fine-structure changing collisions in a cesium magneto-optical trap, reported in a previous work [A. Fioretti
et al., Phys. Rev. A 55, R3999 (1997)], are reanalyzed within a model based on the flux enhancement effect, which takes place in cold atomic collisions.
In the present analysis, we consider the cooperative effect of the long-range and the shorter-range excitation by the strong
trap laser. We evidence also the important role of the hyperfine structure of the Cs2 molecular levels asymptotically connected to the ground-state and excited-state dissociation limits.
Received 22 July 1999 and Received in final form 4 May 2000 相似文献
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