The influence of molecular gases and analytes on excitation mechanisms in atmospheric microwave sustained argon plasmas

Abstract

. (1998). The influence of molecular gases and analytes on excitation mechanisms in atmospheric microwave sustained argon plasmas. Fresenius' Journal of Analytical Chemistry, 362(5), 440-446. DOI: 10.1007/s002160051104General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Abstract The effect of introducing molecular compounds into argon plasmas has been studied using an expanding microwave induced plasma at atmospheric pressure. Besides the use of optical emission spectroscopy (OES), also the time dependent behavior of line intensities during power interruptions has been studied. From the measurements it is found that even an injection of small amounts of molecular compounds (> 0.5%) leads to important changes in excitation mechanisms in the plasma. It is also found that in the recombination zone downstream in the plasma an excitation mechanism which is independent of the electron density, e.g. excitation transfer from metastables or Penning ionization, must be responsible for the excitation of analytes.

Spectroscopic Study of Microwave Induced Plasma

“…This is in qualitative agreement with [29] where detailed study of the influence of molecular gases to the intensity of analyte is outlined. This is in qualitative agreement with [29] where detailed study of the influence of molecular gases to the intensity of analyte is outlined.…”

A Power Interruption Technique for Determining the Difference Between Electron and Gas Temperatures in the Argon d.c. Arc Supplied with Aqueous Aerosol

“…Some important applications of the technique to several spectrochemical sources are: the argon arc, [3,4] the inductively coupled plasma [5,6] and the microwave plasma. [7] The method is based on comparing the population of excited atomic levels before and after the current switch-off. If the population of the observed level is predominantly controlled by the Saha balance, which is the balance of recombination and ionisation by collision with the electrons, and if there is a difference in plasma temperatures between electrons and heavy particles, power switch-off will produce an increase in excited state population, and a jump in the intensity of the spectral line will occur, Eq.…”

Properties of Argon–Nitrogen Atmospheric Pressure DC Arc Plasma

“…Besides, the presence of molecular ions also influences the diffusion, since the diffusion coefficient of the molecular ions is higher than that of atomic ions [41].…”