The determination of low energy electron-molecule cross sections via swarm analysis

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.U ovom radu diskutovane su tehnike razvijene u okviru fizike rojeva elektrona koje ukljucuju resavanje Boltzmannove jednacine i Monte Carlo simulaciju za odredjivanje preseka za sudare elektrona i molekula na niskim energijama. Razvijena je metoda za resavanje Boltzmannove jednacine, bazirana na razvoju funkcije raspodele u red sa proizvoljnim brojem clanova kao i Monte Carlo kod, koji su korisceni za proucavanje vaznih aspekata u transportu elektrona u neutralnim gasovima u uslovima promenljivih konfiguracija elektricnih i magnetskih polja kada nekonzervativni sudari jako uticu na transportne osobine elektrona. Ovi aspekti podrazumevaju proveru validnosti tehnike za resavanje Boltzmannove jednacine bazirane na razvoju funkcije raspodele u red do dva clana po Legendreovim polinomima, tretman nekonzervativnih sudara, uticaj magnetskog polja na transport elektrona kao i prirodu i razlike izmedju transportnih osobina dobijenih u razlicitim eksperimentalnim uslovima. Pokazano je da ovi aspekti transporta elektrona moraju biti pazljivo razmotreni prilikom konstrukcije skupova preseka za rasejanje elektrona na molekulima.