Vol.6, No 1, 2008 pp. 57 - 69
DOI 10.2298/FUPCT0801057D
UDC 539.196
THE DETERMINATION OF LOW ENERGY ELECTRON-MOLECULE
CROSS SECTIONS VIA SWARM ANALYSIS
S. Dujko1,2, R.D. White2,
Z.Lj. Petrović1
1Institute of Physics, University of
Belgrade, Pregrevica 118, Zemun, Serbia
2ARC Centre for Antimatter-Matter Studies,
School of Mathematics, Physics and IT, James Cook University, Townsville
4811, QLD, Australia
Abstract. In this paper we discuss the swarm physics based techniques
including the Boltzmann equation analysis and Monte Carlo simulation technique
for determination of low energy electron-molecule cross sections. A multi
term theory for solving the Boltzmann equation and Monte Carlo simulation
code have been developed and used to investigate some critical aspects
of electron transport in neutral gases under the varying configurations
of electric and magnetic fields when non-conservative collisions are operative.
These aspects include the validity of the two term approximation and the
Legendre polynomial expansion procedure for solving the Boltzmann equation,
treatment of non-conservative collisions, the effects of a magnetic field
on the electron transport and nature and difference between transport data
obtained under various experimental arrangements. It was found that these
issues must be carefully considered before unfolding the cross sections
from swarms transport data.
Key words: Boltzmann equation, electron swarms, cross sections,
transport data.
ODREĐIVANJE PRESEKA ZA SUDARE ELEKTRONA
I MOLEKULA
NA NISKIM ENERGIJAMA ANALIZOM TRANSPORTNIH OSOBINA ROJEVA ELEKTRONA
U ovom radu diskutovane su tehnike razvijene u okviru fizike rojeva elektrona
koje uključuju rešavanje Boltzmannove jednačine i Monte Carlo simulaciju
za određivanje preseka za sudare elektrona i molekula na niskim energijama.
Razvijena je metoda za rešavanje Boltzmannove jednačine, bazirana na
razvoju funkcije raspodele u red sa proizvoljnim brojem članova kao i
Monte Carlo kod, koji su korišćeni za proučavanje važnih aspekata u
transportu elektrona u neutralnim gasovima u uslovima promenljivih konfiguracija
električnih i magnetskih polja kada nekonzervativni sudari jako utiču
na transportne osobine elektrona. Ovi aspekti podrazumevaju proveru validnosti
tehnike za rešavanje Boltzmannove jednačine bazirane na razvoju funkcije
raspodele u red do dva člana po Legendreovim polinomima, tretman nekonzervativnih
sudara, uticaj magnetskog polja na transport elektrona kao i prirodu i
razlike između transportnih osobina dobijenih u različitim eksperimentalnim
uslovima. Pokazano je da ovi aspekti transporta elektrona moraju biti pažljivo
razmotreni prilikom konstrukcije skupova preseka za rasejanje elektrona
na molekulima.
