Colóquio de Física

• Responsável: PPG-FIS
• Câmpus: Santo André
• Local: Auditório A-112-0
• Data: 22/04/2026
• Horário: 15:00 às 17:00
• Descrição:

  Palestrante: Filipe Ferreira da Silva (CEFITEC, Univ. Nova de Lisboa, Portugal)

  Título: Controlling Chemistry with Electrons and Photons

  Resumo:
  Low-energy electrons (LEEs), with energies below ~20 eV, are key drivers of radiation-induced chemistry in a wide range of environments, from nanofabrication to astrochemistry. Among the mechanisms they trigger, dissociative electron attachment (DEA) stands out as a highly efficient and intrinsically energy-selective process, in which transient negative ions lead to bond-specific fragmentation. As a result, chemical reactivity can be tuned by the incident electron energy, enabling selective bond cleavage and controlled reaction pathways. Complementarily, vacuum ultraviolet (VUV) photoabsorption provides direct access to electronic excitation processes, yielding molecular fingerprints that reflect valence electronic structure and excited-state dynamics.

  In the first part of this seminar, will be presented electron-driven processes in EUVL photoresist candidates, focusing on pentafluorophenyl triflate and trifluoromethanesulfonic anhydride as model photoacid generators. In these systems, LEEs can initiate dissociation pathways leading to the formation of acids, a critical step in chemically amplified resist performance. DEA measurements reveal the formation of negative ions and provide insight into the transient anion states and fragmentation channels. Complementary studies on benzonitrile and chlorinated benzonitrile are presented to elucidate how aromatic substitution and halogenation influence electron attachment, anion stability, and dissociation dynamics.

• Necessita inscrição: Não
• Link de divulgação: https://mailchi.mp/a4c4b3f620ba/colquio-de-fsica-2005-s-14h-online-18161399

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