Low-energy electron scattering with polar molecule NH{sub 3} using the R-matrix method

Journal Article · Fri Sep 15 04:00:00 EDT 2006 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.74.032712· OSTI ID:20857709

Munjal, Hema; Baluja, K L ^[1]

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1. Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

We report on the calculated elastic differential, elastic integral, momentum transfer, and excitation cross sections for the low-energy electron-NH{sub 3} scattering using the R-matrix method. Elastic differential and momentum transfer cross sections are obtained by summing over rotationally elastic and rotationally inelastic cross sections for rotor states up to J=4. The excitation cross sections of the first four low-lying electronically excited states from the ground state of NH{sub 3}, at its equilibrium geometry, are presented. These excited states have symmetries a {sup 3}A{sub 1}, A {sup 1}A{sub 1}, b {sup 3}E, and B {sup 1}E. The set of self-consistent-field molecular orbitals is obtained by optimizing these on the first excited state {sup 3}A{sub 1}. Configuration-interaction (CI) wave functions are used to represent the target states. In our CI model, we kept the core two electrons frozen in doubly occupied molecular orbital 1a{sub 1}, and the remaining eight electrons moved freely among the five molecular orbitals 2a{sub 1}, 3a{sub 1}, 1e, 4a{sub 1}, 2e. With this CI model, we obtain good agreement for the vertical spectrum of excited states with the experimental values. The Born approximation is employed to account for higher partial waves excluded in the R-matrix method to evaluate elastic cross sections. Cross sections are reported for the electron-impact energy range 0.025-20 eV.

• OSTI ID: 20857709
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 3 Vol. 74; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
AMMONIA
BORN APPROXIMATION
CONFIGURATION INTERACTION
CROSS SECTIONS
ELECTRON-MOLECULE COLLISIONS
ELECTRONS
EQUILIBRIUM
EV RANGE
EXCITATION
GROUND STATES
MOLECULAR ORBITAL METHOD
MOLECULES
MOMENTUM TRANSFER
PARTIAL WAVES
R MATRIX
ROTATIONAL STATES
ROTORS
SCATTERING
SELF-CONSISTENT FIELD
SYMMETRY
WAVE FUNCTIONS