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Formation and destruction of molecules: the multifaceted and interdisciplinary character of molecular collision and spectroscopy

Kolloquium der Abteilung 6

The formation and destruction of selected polyatomic molecules embedded in our environment will be discussed under the scope of  the time of flight mass spectroscopy technique.  The experimental atomic and molecular collision research performed in the Physics Institute of UFRJ will be presented addressing molecules of  biological and astrochemical interest under impact of radiation -  light and heavy particles and photons -  and the questions will be discussed what is important for molecular survival and fragility.

In recent years, an enhanced interest on the effect of ionizing radiation on the common molecule water, and polyatomic molecules is being observed in diverse interdisciplinary fields. To contribute to biomedicine, astro-chemistry and other fields of study, physicists seek to acquire the necessary information of fundamental processes on the smallest scale.   Experiments have been performed in the electron impact laboratory (EIL), atomic and molecular physics laboratory (LACAM) and Brazilian Synchrotron Light Laboratory (LNLS) investigating ionization, fragmentation and collision dynamics in atomic and molecular collisions.

Experimental results will be presented pinpointing simple molecules as water and methane, and more complex molecules, as DNA bases and analogues biomolecules to access processes relevant for example to radiation damage cause by ionizing agents. The discussion will be extended to polycyclic aromatic hydrocarbons (PAHs), as benzene, cyclohexane, and substituted halo-benzenes in order to tackle the formation of stable double ionized parent molecules and the activation or deactivation of the ring. Isotopically-labelled compounds are included in the discussion stressing out their differences for impact of electrons, protons or photons. The presentation will briefly present the experimental setup developed and operated for these studies.