Calculation of the interspecies s-wave scattering length in an ultracold Na-Rb vapor

We report the calculation of the interspecies scattering length for the sodium-rubidium (Na-Rb) system. We present improved hybrid potentials for the singlet $X^1\Sigma^+$ and triplet $a^3\Sigma^+$ ground states of the NaRb molecule, and calculate the singlet and triplet scattering lengths $a_{s}$ and $a_{t}$ for the isotopomers $^{23}$Na$^{87}$Rb and $^{23}$Na$^{85}$Rb. Using these values, we assess the prospects for producing a stable two-species Bose-Einstein condensate in the Na-Rb system.Comment: v2: report correct units in Table captions, fix error in conclusions for $^{23}$Na$^{85}$Rb TBEC. Otherwise, more concise presentation, typos fixed. 6 pages, 1 figur

Nonradiative lifetimes for LiH in the a state using adiabatic and diabatic schemes

Accurate positions and nonradiative lifetimes of states belonging to the adiabatic A state of LiH are estimated. The results coming from a Golden Rule treatment in the adiabatic scheme present excellent agreement with those obtained through a diabatic close coupling calculation. That confirms the accuracy reached in both approaches and also in the treatment of the diabatic-adiabatic transformation. It involves, in particular, an effective phase control that is needed to properly estimate nonadiabatic couplings. Also, a powerful numerical procedure to obtain energy profiles in the diabatic close coupling frame is described and applied in this work. © 1997 American Institute of Physics.Action Integré Franco-Espagnole n0 96022 for support which has allowed this collaboration.Peer Reviewe

Application of the stabilization method to interacting resonances

The stabilization method is applied to the case of interacting resonances in the photo-dissociation of van der Waals clusters composed by a rare gas atom bound to a dihalogen molecule. The study of an illustrative two-dimensional model consisting in a T-shaped NeI2 molecule shows the adequacy of the method whenever the projection of the stabilization wave functions on the assumed prepared initial state is accounted for. The agreement of the fragmentation cross-sections with some previous results using the effective resolvent method and accurate close-coupling calculations is excellent. The method reveals its utility as a complementary tool since allows, through the analysis of the stabilization wave function in terms of zero-order levels, a precise characterization of the resonant states involved.This work was supported by the joint CSIC-CNRS project 2000FR0029 and the DGICYT Spanish Grant No. BCM2001- 2179. TG-L is indebted to TMR European network, Grant No. HPRN-CT-1999-00007.Peer Reviewe

Quantum dynamics of the collinear CsHH system

International audienc

Mg line profiles for cool WD and their application in the UV

The 21st European Workshop on White Dwarfs was held in Austin, TX from July 23rd to 27th of 2018Since last decade there have been great advances and extremely exciting results in the search and interpretation for cool DZ white dwarfs. In the formation of their spectra, the far wings of alkaline earth metals like Ca and Mg, play an extraordinary role. We present theoretical profiles of theMg resonance lines perturbed by He at the extreme density conditions found in the cool atmosphere of DZ white dwarfs. Atmosphere models are necessary to calculate synthetic spectra and to derive reliable parameters and the atmospheric composition for such objects. We present synthetic spectra tracing the behavior of the Mg resonance line profiles under the low temperatures and high gas pressures prevalent in the cool atmospheres of DZ white dwarfs.Astronom