Theoretical studies of potential energy surfaces and computational methods
- Argonne National Laboratory, IL (United States)
This project involves the development, implementation, and application of theoretical methods for the calculation and characterization of potential energy surfaces involving molecular species that occur in hydrocarbon combustion. These potential energy surfaces require an accurate and balanced treatment of reactants, intermediates, and products. This difficult challenge is met with general multiconfiguration self-consistent-field (MCSCF) and multireference single- and double-excitation configuration interaction (MRSDCI) methods. In contrast to the more common single-reference electronic structure methods, this approach is capable of describing accurately molecular systems that are highly distorted away from their equilibrium geometries, including reactant, fragment, and transition-state geometries, and of describing regions of the potential surface that are associated with electronic wave functions of widely varying nature. The MCSCF reference wave functions are designed to be sufficiently flexible to describe qualitatively the changes in the electronic structure over the broad range of geometries of interest. The necessary mixing of ionic, covalent, and Rydberg contributions, along with the appropriate treatment of the different electron-spin components (e.g. closed shell, high-spin open-shell, low-spin open shell, radical, diradical, etc.) of the wave functions, are treated correctly at this level. Further treatment of electron correlation effects is included using large scale multireference CI wave functions, particularly including the single and double excitations relative to the MCSCF reference space. This leads to the most flexible and accurate large-scale MRSDCI wave functions that have been used to date in global PES studies.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- OSTI ID:
- 139929
- Report Number(s):
- BNL-48923; CONF-9306172-; ON: DE93015758; TRN: 93:002191-0083
- Resource Relation:
- Conference: 15. combustion research contractors` meeting, Lake Harmony, PA (United States), 2-4 Jun 1993; Other Information: PBD: 1993; Related Information: Is Part Of Fifteenth combustion research conference; PB: 391 p.
- Country of Publication:
- United States
- Language:
- English
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