Development of the Nuclear-Electronic Orbital Approach and Applications to Ionic Liquids and Tunneling Processes

摘要

The objective of this research was the development of the nuclear- electronic orbital approach for the investigation of hydrogen bonding and hydrogen transfer systems of interest to the Air Force. In this approach, specified hydrogen nuclei are treated quantum mechanically on the same level as the electrons with molecular orbital techniques. Recent advances within this framework significantly enhance the accuracy and applicability of this approach for the calculation of structures, energies, frequencies, vibronic couplings, and tunneling splittings. This approach was used to examine proton-coupled electron transfer reactions, which are relevant to hydrogen production and fuel cells. Furthermore, this approach was extended to positron systems and used to calculate energies and annihilation rates for small positronic-electronic molecules. Calculations were also performed on hydrogen-bonded clusters relevant to ionic liquids, which are important for the development of highly energetic and environmentally benign propellants.