The project studies the interaction of light (mostly lasers) and charged particles (mostly electrons) with atoms, ions, and small molecules. The results are of importance for the understanding of the fundamental collision dynamics, and they also fulfill the urgent practical need for accurate atomic data to model the physics of stars, plasmas, lasers, and planetary atmospheres. The short-pulse intense-laser part of the project deals with accurate solutions of the time-dependent Schroedinger equation on a numerical space-time grid. With the rapid advances currently seen in computational resources, such studies for realistic rather than idealized model systems have only become possible in recent years. This work is important for further developments in imaging and ultimately controlling of submicroscopic reactions, which is expected to have broad impact by reaching out from physics to chemistry and ultimately biology. Many experimental efforts worldwide are supported through the present project, which will also train a post-doctoral associate and a number of research students in the basic understanding of the problem and the use of highly sophisticated numerical techniques.
Most of the numerical calculations will be based upon the non-perturbative R-matrix (close-coupling) method, as well as direct solutions of the time-dependent Schroedinger equation using various grid-based approaches and basis-function expansions. For single and double ionization of complex atoms by intense atto/femto-second laser pulses, the methods will be combined in such a way that individual parts of the "big problem" can be treated in highly efficient and optimized ways. This strategy will be extended to the treatment of double ionization involving inner shells as well as diatomic molecules. Of particular interest will be the highly challenging, but ultimately necessary simultaneous treatment of the nuclear and electronic motion. There are major difficulties associated with both the formulation of the problem and the subsequent numerical treatment. Much emphasis will be placed on the testing of numerical methods and the visualization of the results, both of which are ideal for student involvement.
