Measurement of the Charge Exchange for N7+, O7+ Ions in Collision with Atomic H

The absolute total cross sections for the charge exchange between highly charged ions 15N7+, O7+, and atomic H have been measured with the ion-atom merged-beams apparatus at Oak Ridge National Laboratory. The collision energy range is from 1224 down to 2 eV u−1, which covers outflowing hot components of astrophysical charge exchange plasmas like stellar-wind and supernova remnants. Good agreement with the previous measurements and theory is found for the collision energies above 100 eV u−1, while below 100 eV u−1 limited agreement is achieved with the available calculations. These cross-section data are useful for modeling X-ray emission resulting from the charge exchange at the interface of hot plasma interacting with ambient neutral gas

Strukturne modifikacije tankih slojeva fulerena pri bombardovanju višestruko naelektrisanim jonima gvožđa

In this paper, the results of structural modification of fullerene thin films bombarded by highly charged iron ions (Fe6+) have been presented. The properties of as-deposited and irradiated fullerene thin films have been investigated by Raman spectroscopy, UV/Vis spectrophotometry and atomic force microscopy (AFM). Results of Raman spectroscopy have indicated structural changes of irradiated thin films depending on fluences. It was found that iron doped fullerene films are dominated by sp3 rather than sp2 bonds after bombardment which might be due to formation of nano-diamond structures. AFM analysis showed that ion beam had destroyed the surface ordering. The optical band gap was found to be in the range of 0.6 to 1.4 eV for irradiated films by Fe6+ ions at the highest fluences.U radu su prikazani rezultati strukturne modifikacije tankih slojeva fulerena koji su bombardovani višestruko naelektrisanim jonima gvožđa (Fe6+). Osobine deponovanih i bombardovanih tankih slojeva fulerena su ispitivane Ramanovom spektroskopijom, mikroskopom atomske sile (AFM), kao i UV/Vis spektrometrijom. Na osnovu rezultata dobijenih Ramanovom analizom može se zaključiti da dolazi do strukturnih promena u bombardovanim fulerenskim slojevima u zavisnosti od doze zračenja. Utvrđeno je da u tankim slojevima koji su bombardovani višestruko naelektrisanim jonima gvožđa dominiraju sp3 veze u odnosu na broj sp2 veza. Dominantno prisustvo sp3 veza u bombardovanim slojevima ukazuje na moguće formiranje dijamantu slične strukture. AFM analiza je pokazala da je promenjena morfologija bombardovanih uzoraka. Utvrđeno je da je energetski procep ozračenih slojeva u opsegu od 0.6 do 1.4 eV u zavisnosti od primenjene doze zračenja