Berlin 2001 – wissenschaftliches Programm

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A: Atomphysik

A 12: Posters Thursday (Ion/Atom/Molecule/Surface Scattering)

A 12.42: Poster

Donnerstag, 5. April 2001, 12:30–15:00, AT3

A Study of the Na-Na Potentials in a Superheated Cell — •Hrvoje Skenderovic, Robert Beuc, Ticijana Ban, and Goran Pichler — Institute of Physics, P.O. Box 304, HR-10001 Zagreb, Croatia

The absorption spectra of alkali-metal vapors can be a rich source of information on atom - atom interaction potentials. The potentials in long-range internuclear distances influence the absorption coefficient in the vicinity of the resonance lines. This spectral region is often blended by the dimer absorption dominated by the bound-bound transitions. In order to reduce dimer absorption and get clear picture of long-range interactions the dimer density can be reduced by superheating. In earlier experiments [1, 2] in a closed cell filled with limited amount of cesium some new spectral features were revealed in superheated conditions. For the study of sodium interactions specially designed heat-pipe oven is prepared following approach from Refs. [3] and [4]. The heat-pipe oven is modified by inserting internal heater that allows for thermal destruction of sodium dimers around the axis. In that way, absorption spectra were obtained where the contributions from the Na2 X - A and X - B bands are significantly reduced. Absorption is also investigated theoretically taking advantage of knowledge recently obtained from ab initio calculations, spectroscopy and ultra-cold atom collision studies. The quantum-mechanical calculations are carried out by the Fourier grid Hamiltonian method [5]. References: [1] T. Ban, S. Ter-Avetisyan, R. Beuc, H. Skenderovic and G. Pichler: Chem.Phys.Lett. 313, 110 (1999). [2] T. Ban, H. Skenderovic, R. Beuc and G. Pichler: Europhys.Lett. 48, 378 (1999). [3] P. J. K. Wisoff and R. G. Caro, Appl. Phys. B 35, 65 (1984). [4] S. Milosevic, R. Beuc and G. Pichler Appl. Phys. B 41, 135 (1986). [5] O. Dulieu, R. Kosloff, F. Masnou-Seeuws and G. Pichler J. Chem. Phys. 107, 10633 (1997).