The main long term goal of this project is to develop theoretical and computational tools that will allow researchers to predict behavior of atomic and molecular systems or explain the results of experiments on atoms and molecules. Because the difficulty in calculating the behavior of these objects grows exponentially with the number of particles, even a small increase in the number of objects can have a huge impact on the effort needed. The main focus of this project is on systems where two or more electrons can simultaneously escape the atom/molecule, or where highly excited atoms are exposed to strong fields. These systems can exhibit highly correlated motion which is difficult to understand without new theoretical or computational techniques.
The broader impact of this project is that it advances the base of knowledge in atomic physics and provides an environment where undergraduates, graduate students and postdoctoral researchers learn the art of scientific research. Young researchers from underrepresented groups are actively encouraged to join this project and they have had good training during previous projects. The results of the research projects are published in peer reviewed journals and presented at divisional meetings, topical workshops, and colloquia, and they can have impact on other scientists.
The main goal of the project was to develop theoretical and computational tools so that we could simulate basic quantum mechanical processes in atoms and molecules from first principles. This is a difficult undertaking because the computational difficulty increases exponentially with the dimensionality so that even a small increase in the number of particles can have a huge impact on effort. Of the many quantum systems we worked on, the main focus is on situations where two or three electrons can escape to infinity or on systems where highly excited atoms are exposed to strong fields. The two or more escaping electrons is important because correlation between them develops over large distances due to their mutual repulsion from their like charges. Highly excited atoms are important because it is possible to experimentally control the way that energy and particles flow through the different degrees of freedom and because of their possibilities for quantum information. We have successfully improved our computational techniques so that we can now perform simulations for a wide variety of situations. We now routinely perofrm calculations with two electrons in almost any situation investigated experimentally. Most experiments involve start with two electrons in the outer, valence shell, as with the atoms hellium, berrylium, magnesium, etc. The electron dynamics can be triggered by light, passing ions, etc. Calculations with three active electrons are more difficult but can now be treated in many circumstances (for example, electrons scattering from an atom with two valence electrons or light interaction with three electron systems like lithium). Calculations for highly excited atoms have also improved to the point where it is routine to study systems 10,000 times larger than for typical atoms or over times scales a million times longer than typical. Our other areas of interest have experienced similar advances. These investigations advance the base of knowledge in atomic and molecular physics and provides an environment where undergraduates, graduate students and post-doctoral researchers learn the art of scientific research. The students learn how to develop computer programs needed to simulate important basic processes and how to interact with scientists involved with experiments to aid in the understanding of their results.
