Effect of plasma composition on chemical and physical events in the direct current plasma

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:7044376

Mangold, R A

Analytical atomic emission spectroscopy has been advanced greatly by the introduction of the plasma as an emission source. In this investigation the chemical and physical effect of plasma composition are studied. The plasma composition was changed by the introduction of other gases into a direct current plasma (DCP). The gases studied here are nitrogen and helium. The atomization efficiency was determined by the degree of dissociation of the refractory metals in the plasma. The excitation temperatures were determined by using a series of Fe lines. The electron densities were determined by the absolute measurement of the continuum intensity in the plasma. Because of errors in the literature, a comprehensive derivation and presentation of the theory involved in continuum measurements is given. Nitrogen was introduced as a nebulization gas into the plasma. The effect of the substitution of the nebulization gas was evaluated. The operation of the plasma under these conditions was favorable with most analyses showing only marginal degradation with the exception of the refractory compounds. The increase in molecular background was determined to be only marginal since this could be avoided by a prudent choice of analysis wavelength. The use of He in the DCP was applied in three ways: nebulization with He into a Ar plasma, the use of He/Ar mixtures as the plasma and an all-He plasma. The methods in which he was used with Ar showed little improvement. However, when an all-He plasma was investigated, the added excitation from the He excited states made possible the detection of the halogens by non-resonant emission. Detection limits for all systems were determined.

• Research Organization: Texas A and M Univ., College Station (USA)
• OSTI ID: 7044376
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102* -- Chemical & Spectral Procedures
ARGON
ATOMIZATION
CHEMICAL COMPOSITION
DETECTION
ELECTRON DENSITY
ELEMENTS
EMISSION SPECTROSCOPY
ENERGY LEVELS
EXCITED STATES
FLUIDS
GASES
HALOGENS
HELIUM
KINETICS
NITROGEN
NONMETALS
PLASMA
RARE GASES
REACTION KINETICS
SPECTROSCOPY
TEMPERATURE MEASUREMENT