Current Research Topics:

• Accurate determination of cross sections and rates coefficients for electron collisional excitation to the n=5 states of HeII ions.
• Photoionization of the excited (1snl) states of atomic helium and the determination of radiative recombination coefficients.
• Inner shell photoionization of Oxygen atoms in the soft X-ray region.
• Fine structure electron collisional excitation cross sections and rates for low lying states of OII ions.
• Dissociative recombination, elastic scattering, electronic and vibrational excitation for electron collisions with the diatomics He$_2^+$, N$_2$, CH and polyatomic H$_3^+$ molecules.
• Excitation of atomic hydrogen by proton impact to the n=3 states determining the Lyman-alpha and Balmer-alpha cross sections.
• Destruction cross sections for Rydberg-atom collisions between atomic hydrogen atoms.

High Performance and Parallel Computing in my research:

The application of high performance computers (HPC) to atomic and molecular collision problems offers the prospect of dramatically broadening the scope and scale of research. Supercomputers or farms of high speed work stations make possible an enhanced level of sophistication and confidence in numerical predictions. Complicated experiments can be better interpreted, and results can be extrapolated in cases where no measurements are practical. Numerical experiments frequently display evidence of patterns that would not otherwise have been suspected. In combination with modern graphical techniques of 3D, color, and animated presentations, they provide ways of visualizing results which exist in spaces of many dimensions. Such visualization leads to new insights and theoretical models. The facility with which computers can be used to monitor time-dependent phenomena opens a broad range of inquiry. The evolution of atomic and molecular densities in ion-atom, atom-atom or electron-molecule collisions and following intense laser pulses are obvious examples in atomic and molecular physics.

Numerical experiments frequently display evidence of patterns that would never otherwise have been suspected. The search for explanations of them can then lead theory in unexpected directions. Well-known applications of visualization and pattern recognition occur in chaos and non-linear dynamics. Supercomputers help immensely in the generation and simulation of large amounts of data for applications. Presently and more so in the future they will play an essential role in archiving and retrieving such data efficiently. Various areas of applications of atomic and molecular data are in astrophysical and laboratory plasmas, planetary ionospheres and the interstellar medium.

For many problems in atomic and molecular collisions, the use of present day and projected computing power will have a profound impact. An example is low-energy ion-atom and atom-atom collisions, where extremely large numbers of channels should properly be included or a numerical discretization procedure used. The problem can be reduced to solving large numbers of ordinary differential equations in parallel, a task ideally suited for massively parallel computer architectures. Realizing the potential of current and projected design of computers in the coming decade will open new avenues to explore in atomic and molecular physics. This work will allow interdisciplinary interactions with various areas of theoretical and computational physics, and contacts with experiments.

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