engleski

Ion-pair satellite bands in heavy alkali dimers : ultracold ion-pair molecule

We present results of absorption measurements in dense cesium, rubidium and potassium vapor generated in all sapphire cells (1,2). New spectral features of satellite bands in the neighbourhood of the second member of the cesium, rubidium and potassium principle series were found. We established no temperature dependence of two peculiar diffuse features in the blue wing of the stronger component np3/2, n = 5, 6, 7 for potassium, rubidium and cesium, respectively). By applying recent ab initio otential curves at large distances, we were able to construct corresponding difference potential urves with extrema responsible for the observed satellite bands. It appears that these extrema stem from the system of two close lying avoided crossings between ion-pair potential curve and long-range van der Waals potential curves emerging from several eighbouring atomic asymptotes (which also include second excited doublet of the p levels). The uppermost difference potential curve has one minimum and one maximum at very large interatomic distances, which in effect realizes bound electronic state of pure ion-pair character. The imlplications and aspects of such potentials for the case of ultracold K_2, Rb_2 and Cs_2 molecules will be discussed. ______________________________________________ [1] T. Ban, H. Skenderović, R. Beuc and G. Pichler, Europhys. Lett. 48 (1999) 378 ______ [2] T. Ban, S. Ter-Avetisyan, R. Beuc, H. kenderović and G. Pichler, Chem. Phys. Lett. 313 (1999) 110

Ion-pair satellite bands; ultracold ion-pair molecules; heavy alkali dimers

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