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Computational Study of Electron-Molecule Collisions Related to Low-Temperature PlasmasComputational study of electron-molecule collisions not only complements experimental measurements, but can also be used to investigate processes not readily accessible experimentally. A number of ab initio computational methods are available for these types of calculations. Here we describe a recently developed technique, the finite element Z-matrix method, Analogous to the R-matrix, method, it partitions the space into regions and employs real matrix elements. However, unlike the implementation of the R-matrix method commonly used in atomic and molecular physics, the Z-matrix method is fully variational. In the present implementation, a mixed basis of finite elements and Gaussians is used to represent the continuum electron, thus offering full flexibility without imposing fixed boundary conditions. Numerical examples include the electron-impact dissociation of N2 via the metastable A3Su+ state, a process which may be important in the lower thermosphere, and the dissociation of the CF radical, a process of interest to plasma etching. To understand the dissociation pathways, large scale quantum chemical calculations have been carried out for all target states which dissociate to the lowest five limits in the case of N2, and to the lowest two limits in the case of CF. For N2, the structural calculations clearly show the preference for predissociation if the initial state is the ground X1 Sg+ state, but direct dissociation appears to be preferable if the initial state is the A3Su+ state. Multi-configuration SCF target functions are used in the collisional calculation.
Document ID
20020052401
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Huo, Winifred M.
(NASA Ames Research Center Moffett Field, CA United States)
Partridge, Harry
Date Acquired
August 20, 2013
Publication Date
January 1, 1997
Subject Category
Plasma Physics
Meeting Information
Meeting: 50th Annual Gaseous Electronics Conference
Location: Madison, WI
Country: United States
Start Date: October 6, 1997
End Date: October 9, 1997
Funding Number(s)
PROJECT: RTOP 242-80-01
PROJECT: RTOP 244-15-40-11
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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