Seminário do Departamento de Física, CEFITEC e LIBPhys. Paulo Limão-Vieira: “Decomposition of biological molecular targets by electron transfer experiments”

Orador: Professor Paulo Limão-Vieira

“Decomposition of biological molecular targets by electron transfer experiments”

In this project we probe negative ion formation through electron transfer in neutral potassium(K)-biomolecule collision experiments to investigate the nature of specific low-lying excited states of some modified DNA/RNA subunits and simple side chain aminoacids. To achieve this, we have equipped the crossed molecular beam apparatus with a commercial reflectron time-of-flight (TOF) mass spectrometer (mass resolution better than 3000) and installed a K+ energy loss analyser. Such a combination allows us to explore for the first time negative ion formation and their related anionic states through the energy transferred in the collision process, i.e. through the K+ energy loss profiles. As such, we are focusing our interest in exploring molecular negative ion states that lead to the formation of simple radical units, e.g. those yielding the dehydrogenated parent anion + H•, the double dehydrogenated parent anion + H• + H• or + H2, parent anion with loss of OH•, and infer on the role of the neutrals’ formation.