Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Theoretical studies of electronically nonadiabatic and spin-forbidden processes

Thesis/Dissertation ·
OSTI ID:111297
Recent advances in computational techniques to characterize electronically nonadiabatic and spin-forbidden processes will be illustrated. These techniques will be used within the context of ab initio electron structure state averaged-multiconfiguration self consistent field (SA-MCSCF)/configuration interaction (CI) methods. For nonadiabatic processes, a newly developed approach, based on analytic gradient techniques, will be employed to locate regions of crossings/avoided surface crossings, and to calculate first derivative nonadiabatic coupling matrix elements. Two studies of nonadiabatic processes will be presented: (1) The determination of an actual crossing seam for the charge transfer reaction H{sup +} + NO {yields} H + NO{sup +}. This is the first time a crossing of two states of the same symmetry is reported for a charge transfer reaction. (2) The determination of an avoided crossings seam in the reactive quenching process Li({sup 2}S) + HCl and Li({sup 2}P) + HCl, respectively, is key to understand the quenching mechanism of this reaction. First derivative nonadiabatic coupling matrix elements will be reported in the vicinity of the seam to characterize the propensity of a nonadiabatic transition. The description of spin-forbidden processes to be studied require the incorporation of spin orbit effects. These effects will be treated within the Breit-Pauli approximation. Two applications of spin-forbidden processes will be discussed.
Research Organization:
Johns Hopkins Univ., Baltimore, MD (United States)
OSTI ID:
111297
Country of Publication:
United States
Language:
English