Atomic and Molecular Collisions
The Atomic and Molecular Collisions Laboratory (LCAM) was established in 2004 with the main purpose to explore the electronic state spectroscopy of aeronomic, plasma processing, interstellar medium (ISM) and biological relevant molecules by interaction with photons and electrons. LCAM’s unique nature within NOVA School of Science and Technology has allowed to comprehensively investigate environmental selected molecules related to global warming and ozone depletion, while modelling photolysis rates and local lifetimes in the Earth’s atmosphere (0-50 km altitude). Such unique asset has been earlier recognized as a relevant partnership with governmental and non-governmental organizations across the globe for database repositories ever since.
At the forefront of worldwide interest in electron induced processes at the molecular level, LCAM assembled a unique gas-phase crossed molecular beam setup to explore electron transfer to biological relevant molecules, e.g. DNA/RNA nucleobases and even nucleosides. Additionally, and given the role of modern tailor-made radiation induced protocols for cancer treatment, radiosensitizers have been comprehensively investigated in order to provide essential information as to the underlying molecular mechanisms relevant to radiosensitization in redox processes.
Further to LCAM’s mission and installed technical abilities, new gas-phase experimental setups have been successfully installed to explore the electronic and molecular structure of a diversity of molecules, either through high-resolution electron energy loss or He(I) photoelectron spectroscopies. Since its foundation, LCAM keeps relevant international partnerships with universities and reference research laboratories, at the national and international scenes, with the main purpose to reinforce and bring in contributions of complementary experimental and theoretical techniques essential for its indoors scientific achievements. Also central to our mission is undergraduate and postgraduate advanced training which we have successfully performed by attracting national and international students.
LCAM is a full member within Centre of Physics and Technological Research (CEFITEC) research programme UID/PRR/00068/2025
For further information on Professor Limão-Vieira visit his webpage
Laboratory Facilities
Electron transfer experiment in atom-molecule collisions
The main research goals are the study of the dynamics of negative ions formed by charge transfer in atom-molecule collisions, with the special attention to biomolecular systems.
The electron transfer experiment consists of two high-vacuum pumped chambers: the potassium chamber and the collision chamber. We make use of a crossed molecular beam technique, where a fast hyperthermal atomic beam (potassium), produced in a resonant charge exchange chamber, crosses at right angles an effusive molecular target in the collision chamber.
The intensity of the primary beam (potassium) is monitored by an iridium surface detector, especially designed for alkalis. The molecular beam target (secondary beam) is produced by effusion of a gas, liquid or heating a solid sample in an oven. The ions formed in the interaction region (positive and negative) are extracted into a homemade TOF and mass analysed. Kinetic energy release distributions may also be obtained.
High Resolution Electron Energy Loss Spectroscopy (HREELS)
We investigate the electronic state spectroscopy of gas-phase molecular targets in dipolar and non-dipolar conditions in a High Resolution Electron Energy Loss Spectroscopy (HREELS) setup.
The HREELS experiment consists of one high-vacuum chamber with an electron monochromator capable of an energy resolution of 30 meV. We make use of a crossed molecular beam technique, where the electron beam is scattered by an effusive molecular target. The electron energy loss is probed by an hemispherical analyser.
He(I) Photoelectron Spectroscopy (PES)
We have installed a He(I) Photoelectron Spectroscopy (PES) setup for probing low-lying ionic states in molecular targets.
The PES experiment consists of a high-vacuum chamber coupled with a He(I) source. The spectrometer consists of a 180° cylindrical electrostatic analyser with a mean radius of 5 cm. The analyser is used in constant energy pass mode.
The incident photons are produced by a D.C. discharge in a two stage differentially pumped lamp. The energy scale is calibrated using the well-known argon lines (2P3/2 and 2P1/2) and the resolution at the full width half maximum (FWHM) of the Ar peaks is usually as best as 30 meV. The accuracy of the energy scale is estimated to be ± 2 meV.
Members
Permanent Staff
Professor Paulo Limão-Vieira (Head of Research)
Email: plimaovieira@fct.unl.pt
Room: 243 – I
Tel: (+351) – 21 294 78 59 Ext. 10570
Professor Manuel Maneira
Email: mjpm@fct.unl.pt
Room: 243 – I
Tel: (+351) – 21 294 85 76 Ext. 10535
Professor Pedro Pereira
Email: ppereira@deq.isel.ipl.pt
Room: 123 – I
Tel: (+351) – 21 294 85 76 Ext. 10535
Collaborators
Dr Sarvesh Kumar
Email:
Room: 123 – I
Tel: (+351) – 21 294 85 76 Ext. 10537
PhD students
Mrs. Elahe Mahmoudi
Email: e.mahmoudi@campus.fct.unl.pt
Room: 257 – I; Lab: 123 – I
Tel: (+351) – 21 294 85 76 Ext. 10512
Mr. Pedro Alfieri Schadeck Randi
Email: pasr@fisica.ufpr.br
Room: 257 – I; Lab: 123 – I
Tel: (+351) – 21 294 85 76 Ext. 10512
Ms. Umma Salma Akther
Email: u.akther@campus.fct.unl.pt
Room: 257 – I; Lab: 123 – I
Tel: (+351) – 21 294 85 76 Ext. 10512
Collaborations
International
Departamento de Física, Universidade Federal do Paraná, Brazil
Professor Márcio H. F. Bettega
Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Madrid, Spain
Professor Gustavo García
Institute for Storage Ring Facilities, Aarhus University, Denmark
Dr Søren Vronning Hoffmann and Dr Nykola Jones
Université de Tunis el Manar & Université de la Manouba, Tunisia
Professor Boutheïnia Kerkeni
Department of Physics, Sophia University, Tokyo, Japan
Professor Hiroshi Tanaka and Professor Masamitsu Hoshino
Institut für Ionenphysik, Leopold Franzens Universität, Innsbruck, Austria
Professor Stephan Denifl and Professor Paul Scheier
Laboratoire de Physique des Lasers, Université des Sciences et Technologies de Lille, France
Professor Denis Duflot
Department of Physical Sciences, The Open University, UK
Prof. Samuel Eden
National
ISEL – Instituto Superior de Engenharia de Lisboa
Professor Pedro Pereira
UCIBIO – Rede de Química e Engenharia Química e Bioquímica em Portugal (UCIBIO/REQUIMTE)
Professor Alice S. Pereira and Professor Pedro Tavares
