- Theoretical study of basic reactions of electron excitation, capture and ionization by impact of heavy ions (naked and dressed) and light projectiles (electrons and positrons) at intermediate and high impact energies with atomic and molecular targets.
- Photoionization of atoms and molecules by impact of photons at high and intermediate energies.Applications of the Atomic Collision Theory to Radiobiology.
- Energetic dose in biological matter at micro- and nano-metric level.
- i>Ionization of liquid water by electron impact at intermediate and high impact energy.
- Fragmentation of water molecules and biological molecules.Attophysics.
- Photoionization of atoms and molecules by attopulses assisted by infrared lasers.
Atomic and Molecular Physics is a basic field of Physics that deals with phenomena occuring at the atomic and molecular scale. In particular, the study of Atomic Collisions is an area of research providing knowledge and basic ideas for the understanding of the structure of matter as well as its interaction with charged particles and radiation. The reactions of interest include excitation, electron capture and ionization of atoms and molecules by impact of charged particles and photons.
Nowadays, there is a great variety of research activities in this field going from interactions with multiply charged ions to design last generation atomic clocks or to perform precise measurements of Ly-α1 transitions to test the QED in presence of strong fields, to the implementation of equipments useful in Quantum Computing, as well as the development of the ‘molecular spectroscopy’. To reach the latter one, interference patterns produced in ‘molecular double-slit’ experiments in which the two centers of diatomic molecules play the role of the two slits are analyzed. For instance, we show the angular distribution of photoelectrons with de Broglie wavelength λe emitted from a H2(in red) molecule of internuclear distance R: the maxima (n=1,2,3,...) are observed at angles θe analogous to the ones of the Young two-slit experiment.
Moreover, the comprehension of the studied phenomena allows the application to other areas such as Radiobiology where it is of prime importance the knowledge at micro- and nanometric scale of the energy deposition process in the living matter through the passage of the so called ionizing radiations. These tasks give information about the damage provoked to cellular DNA and RNA that is useful to the development and planning of radiant therapies to treat thumors.
In addition, very recently a new reaserch field called ‘attophysics’ has emerged. Work in this area is focused on the ionization reactions by ultrashort laser pulses (in the extreme ultraviolet, XUV) of hundreds of attoseconds of duration (1 attosecond= 10-18s) assisted by lasers in the near infrared (NIR). As an example, we sketch the ionization of a diatomic molecule (nuclei in green) by the action of an XUV attopulse (in purple) in the presence of NIR laser (in red), both with circular polarization. The final momenta distribution of the ionized electron may be ‘sculpted’ by means of the interferences produced by the existence of the NIR laser giving place to preferential products in the final channel of the reaction (i.e., ionized or fragmented molecule). So, one of the goals pursued in attophysics is the control of the chemical reactivity.