Emission Characteristics of a Low-Pressure Laser-Induced Plasma: Selective Excitation of Ionic Emission Lines of Copper

Under reduced pressures, the plasmas produced by irradiation of a Q-switched Nd:YAG laser have favorable features as an excitation source for solid samples in atomic emission spectrometry, such as relatively low fluctuation of the emission intensity and a high signal-to-background ratio. For the analytical application of low-pressure laser-induced plasma spectroscopy (LP-LIPS), the spectra should be examined regarding the type of emission lines and their relative intensities. Further, information on the excitation mechanism in the plasma could be useful in determining optimum operation conditions of the experimental parameters. Spectrum patterns of LP-LIP are principally determined by the type of the filled gas. Especially, particular ionic lines of Cu are selectively excited when Ar or Ne are employed as the filled gas. This feature seems to be due to the (quasi-) resonance charge transfer collisions between a ground state ion of the Ar or Ne gas and a ground state atom of Cu. The plasma plume expanding after the laser irradiation also becomes an excitation source for sample atoms introduced by laser ablation.

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Fourier Deconvolution of Overlapping Line Pairs in Inductively Coupled Plasma-Atomic Emission Spectrometry

Applied Spectroscopy ◽

10.1366/0003702894202049 ◽

1989 ◽

Vol 43 (1) ◽

pp. 96-103 ◽

Cited By ~ 10

Author(s):

Eric H. Van Veen ◽

M. Pieter Goudzwaard ◽

Margaretha T. C. De Loos-Vollebregt ◽

Leo De Galan

Keyword(s):

Inductively Coupled Plasma ◽

Gaussian Approximation ◽

Signal To Noise Ratio ◽

Detection Limits ◽

Atomic Emission ◽

Emission Lines ◽

Emission Spectrometry ◽

Plasma Atomic Emission Spectrometry ◽

Spectral Window ◽

Inductively Coupled

A deconvolution procedure utilizing Fourier transformation has been developed to reduce line overlap in ICP-AES. Line broadening is caused by physical processes and by instrumental broadening. Convenient deconvolution, however, turns out to be restricted to broadening common to the emission lines in the spectral window, i.e., to instrumental broadening. Deconvolution for the “true” instrumental broadening function and for a Gaussian approximation to this function yields similar results, but the former allows for fast automated data processing with regard to any spectral region and sample composition. A straightforward procedure is reported for the determination of this function independent of wavelength. At the present noise level, a twofold reduction in linewidth can be achieved for emission lines having a small physical width in comparison to the instrumental width. With data acquired from both a high- and a medium-resolution monochromator, results from overlapping line pairs show linear analytical curves and improved detection limits. Due to the decrease in signal-to-noise ratio on deconvolution, the detection limits measured for isolated lines cannot be attained.

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