Heidelberg 2015 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
MO: Fachverband Molekülphysik
MO 13: Collisions & Energy Transfer
MO 13.4: Vortrag
Mittwoch, 25. März 2015, 12:00–12:15, PH/SR106
Collective excitation in energetic proton collision with naphthalene — •Preeti M Mishra1,2, Jyoti Rajput3, C P Safvan4, Sarita Vig1, and Umesh Kadhane1 — 1Indian Institute of Space Science and Technology, Trivandrum-695547, India — 2Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany — 3University of Delhi, Delhi-110 007, India — 4Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi-110 067, India
The structural and dynamical study for Polycyclic aromatic hydrocarbons (PAHs) is important in astrophysics as well as in medical science. Due to delocalized electrons, PAHs show collective excitation characterized by large oscillator strength which are difficult to isolate from other physical processes due to broader energy deposition in ion-molecule collision. The contribution of collective excitation is distinctly identified in ionization and evaporation processes (H, 2H, C2H2 loss) in proton (50-180 keV) collision experiments with gaseous naphthalene at IUAC, New Delhi using an electron cyclotron resonance ion source. The photoelectron spectroscopy with pyrene and fluorene showed that collective excitation is coupled to inner valence shell and hence a good amount of excitation energy goes in heating which leads to above evaporation process. In the direct ionization mode, two mechanisms are active in the collision process: large impact parameter plasmon excitation mode and closer encounters with higher amount of electronic energy loss leading to fragmentation, whereas the resonant electron capture process was found to be associated with less electronic energy loss.