Ab initio calculations of processes in low-energy electron-molecule scattering

Thesis/Dissertation · Mon Jan 01 04:00:00 EST 1979

OSTI ID:5434363

Levin, D A

Calculations are reported for low energy e-N/sub 2/ scattering cross sections in the static-exchange approximation. The approach used involves solving the Lippmann-Schwinger equation for the transition operator in a sub-space of Gaussian functions. New features of the method are analytic evaluation of matrix elements of the free particle Green's function and analytic transformation to obtain single-center expansion coefficients for the scattering amplitude. Cross sections are presented for e/sup -/-CO scattering in the static exchange approximation. Results are also presented for rotational and vibrational-rotational excitation of H/sub 2/ by electron impact in the static-exchange approximation. Vibrational and vibrational-rotational excitation cross sections of N/sub 2/ by electron impact via the /sup 2/II/sub g/ resonance in the static-exchange approximation are obtained. To obtain highly accurate phase shifts in the II/sub g/ channel the variational correction of Fliflet and McKoy applied to the discrete-basis-set method of Fliflet, Levin, Ma and McKoy is used. As in e-H/sub 2/ vibrational excitation, the approach involves solving the fixed-nuclei scattering problem at several internuclear separations. A simple model to include polarization effects in shape resonances is discussed next. An important refinement of the original T-matrix method is the analytic evaluation of Gaussian matrix elements of the free particle Green's function.The derivation of a method for generating higher order Gaussian matrix elements is presented. Although this procedure is applicable to polyatomic systems, only the types of matrix elements necessary for ..sigma.., II and ..delta.. symmetries of a linear molecule are listed. Finally, a method for obtaining scattering wave functions at arbitrary energies is presented.

• Research Organization: California Inst. of Tech., Pasadena (USA)
• OSTI ID: 5434363
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
AMPLITUDES
ATOM COLLISIONS
COLLISIONS
COMPARATIVE EVALUATIONS
CROSS SECTIONS
DATA
ELECTRON COLLISIONS
ELECTRON-ATOM COLLISIONS
ELECTRON-MOLECULE COLLISIONS
ELEMENTS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EQUATIONS
EV RANGE
EV RANGE 01-10
EXCITATION
FLUIDS
FUNCTIONS
GASES
GAUSSIAN PROCESSES
GREEN FUNCTION
HELIUM
HYDROGEN
INFORMATION
INTEGRAL EQUATIONS
LIPPMANN-SCHWINGER EQUATION
MATRICES
MOLECULE COLLISIONS
MOMENTUM TRANSFER
NITROGEN
NONMETALS
NUMERICAL DATA
POLARIZATION
RARE GASES
RESONANCE
S MATRIX
SCATTERING
SCATTERING AMPLITUDES
THEORETICAL DATA
WAVE FUNCTIONS