Comprehensive Interferometric Characterization of Red and Near-Infrared Emissions of C,H,N,O,F,Cl,Br,I,P,S,and Si in a 370-W Microwave-Induced Helium Plasma

Abstract

The red/near-infrared emission spectrum from a 370-W atmospheric pressure helium microwave-induced plasma (MIP) has been characterized for eleven nonmetals with a Fourier transform spectrometer and silicon photodiode detector. A comprehensive list of all observed lines and relative intensities has been tabulated for MIP-excited emissions of C, H, N, O, F, Cl, Br, I, P, S, Si, and the helium background in the diode detector region 15,750 to 8500 cm⁻¹ (6349–11,764 Å). Many of these red/near-infrared lines (especially of phosphorus and silicon) are reported for the first time in an analytically useful plasma. Data for silicon and phosphorus are shown to fit known Grotrian diagrams. The data of this paper were used with corresponding known upper-state energies and transitions to construct a partial Grotrian diagram for helium plasma emissions of iodine.