Comparison of laser-induced breakdown spectra of organic compounds with irradiation at 1.5 and 1.064 microm.

A comprehensive investigation of laser-induced breakdown spectroscopy (LIBS) at 1.500 microm of residues of six organic compounds (anthracene, caffeine, glucose, 1,3-dinitrobenzene, 2,4-dinitrophenol, and 2,4-dinitrotoluene) on aluminum substrates is presented and compared with LIBS at the Nd:YAG fundamental wavelength of 1.064 microm.

Comparison of IR and UV cavity ring-down spectroscopy detection of transient intermediates: pyrolysis of methyl azide to form methyleneimine.

Mid-infrared cavity ring-down spectroscopy (CRDS) has been employed in this study to examine the hydride stretching region of methyl azide and its pyrolysis product methyleneimine. The absorption spectrum of methyl azide over 2835-3085 cm(-1) was recorded, and the integrated absorption cross section was determined. The pyrolysis of methyl azide and subsequent production of methyleneimine was observed at various wavenumbers.

Improved dispersion of bacterial endospores for quantitative infrared sampling on gold coated porous alumina membranes.

An improved method for qualitative and quantitative sampling of bacterial endospores using Fourier transform infrared (FT-IR) microscopy on gold-coated porous alumina membranes is presented. Bacillus subtilis endospores were filtered onto gold-coated alumina membranes serving as substrates. Studies in the mid-infrared (MIR) region revealed the characteristic bacterial absorption spectrum at low surface concentration, while scanning electron microscopy (SEM) images of the same samples provided precise calculation of the surface concentration of the bacterial endospores.