Berlin 2001 – wissenschaftliches Programm

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MO: Molekülphysik

MO 8: Posters Thursday: Dissociation and other Collision Processes

MO 8.27: Poster

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

CHARGE TRANSFER AND IONIZATION IN SLOW COLLISIONS OF K + IONS WITH . . — •M. Gochitashvili, B. Kikiani, R. Lomsadze, and N. Mosulishvili — Physics Department, Tbilisi State University, 1.Chavchavadze Avenue, Tbilisi, 380028 Georgia

Physics Department, Tbilisi State University, 1.Chavchavadze The absolute values for differential and total cross sections of electron capture and ionization processes during collisions of K + ions with H2 and N2 molecules in the 0.5-6.0 keV energy range are measured. The measurements were carried out by collision and optical spectroscopy methods. The experimental set up are described in detail 1,2 . . The potassium ion beam extracted from a surface ionization ion source, after acceleration, focusing and magnetic mass-analyse has crossed a narrow (interaction area  0.5 mm3) thermal energy molecular gas. The fast neutral atoms of K formed as a result of collision are separated from a charge component by transverse electrostatic field and were registered by detector which was rotating around the centre of interaction area in the angle interval 30 0 with the resolution of 0.2 0 . The investigations have shown that at list for K + -N2 pairs the collision particles are scattered on large angles and their collection are connected with experimental difficulties. Therefore, at first the differential cross-section of these processes was measured and then total cross sections were restored. It was found that the angular dependence of differential cross sections for charge transfer processes have a threshold behaviour around the reduced scattering angle of 6-8 keV.deg. and are connected with mechanism of the pseudo-crossing of the quasimolecular potential energy terms of corresponding states. The excitation of resonance Line of KI (.... =766.5 nm, transition 4p 2 D-4s 2 S) has been measured as wall. Comparison of the electron capture cross section in the excited K (4P) states with the total cross section shows that the capture of electrons for both cases take place in the ground K (4S) state mainly. This fact is confirmed by analyse of schematic correlation diagram, which was constructed in framework of quasidiatomic approximation. It was found that electron capture in the ground K (4S) State caused by .- .type interaction 1. B.Kikiani., R.Lomsadze. N.Mosulishvili - Bulletin of Georgian Academy of Sciences, 3 (1995) 394. 2.M.Gochitashvili ,Njaliashvili,Rkvizhinadze,B.Kikiani J.Phys.B281 (1995) 2453.