An ab-initio quantum chemistry program MELD will be maintained, updated and distributed without charge. New features such as a parallel computer direct configuration interaction method with importance selection will be implemented. An improved eigenvalue method will be developed and distributed in a stand-alone form for incorporation with other programs. Applications will be made to interesting problems in spectra, reactivity and structure. The collaborations will continue with the ESR studies, the EMS studies and the PES studies. The PI will also continue studies of organic reactions involving biradical intermediates. A part of this research will be the development of tools to better study iron sulfur complexes of importance to biology. Modern quantum chemical theoretical methods will be developed and used to study a variety of reactions of importance in both chemistry and biochemistry. In particular these methods will be extended to enable the study of large systems on new and emerging massively parallel computers. The methods involve the sophisticated evaluation of accurate energies and structures for a number of iron-sulfur containing compounds which prove particularly challenging theoretically.
