Application of Molecular Emissions in Laser-Induced Breakdown Spectroscopy: A Review

Abstract

Laser-induced breakdown spectroscopy (LIBS) with advantages of rapid, in situ, and little sample pretreatment has been used in various fields. However, LIBS technology remains challenging in the detection of halogens, isotopes, and samples with similar elements. Therefore, molecular emission was proposed to improve the detection ability of LIBS. In this review, we introduced molecular emissions formed by organic elements, oxidizable elements, and halogens. Then, molecular emission in different experiment parameters, such as the acquisition window, laser characters (laser energy, laser wavelength, and pulse duration), and ambient atmospheres, were discussed. In the end, we highlight the application of molecular emissions on element content determination, material type classification, and combustion and explosion process monitoring.

Comparative Long-Wave Infrared Laser-Induced Breakdown Spectroscopy Employing 1-D and 2-D Focal Plane Array Detectors

“…Acetaminophen (C 8 H 9 NO 2 Figure 3 ) is an organic compound which is widely used as a pharmaceutical pain reliever. In the UV/Vis/NIR LIBS spectrum of acetaminophen ( Figure 2 a,b), emission signatures due to electronic transitions of typical atomic and di-atomic constituents of an organic compound could be observed: C atoms at 422 nm, 466 nm, and 553 nm; H atoms at 383 nm, 410 nm, 486 nm, and 656 nm; N atoms at 451 nm, 500 nm, 747 nm, 822 nm, 868 nm, 905 nm, and 939 nm; O atoms at 375 nm, 444 nm, 777 nm, 795 nm, 845 nm, and 926 nm; a di-atomic CN molecule at 388 nm and 415 nm; and a di-atomic C 2 molecule at 467–473 nm and 513–516 nm [ 14 , 15 ]. In the LWIR LIBS spectrum of pure acetaminophen, several intense molecular vibrational emission features could be readily observed between 5.6 and 10 µm.…”

Laser-Induced Breakdown Spectroscopy Imaging for Material and Biomedical Applications: Recent Advances and Future Perspectives

“…134 The strategy to indirectly analyze the distribution of an element via the use of molecular emission from plasma is very relevant and contradictory to the general dogma claiming that LIBS is efficient for analyzing chemical elements alone, without knowledge about the molecular information. The application of molecular emissions in LIBS is indeed a growing area of research, 135 and we believe that there are many benefits to developing innovative LIBS imaging projects that also include molecular emission analysis. Recently, both elemental and molecular emissions were studied within a single project aiming at studying cancer in an animal model.…”

Atomic spectrometry update: review of advances in the analysis of metals, chemicals and materials

“…This was presented (with 86 references) by Xu et al and was on the subject of molecular emission from LIBS. 11 Topics discussed included molecules of organic origin, e.g. -OH, -CH, -NH, -CN and C 2 and molecules formed to facilitate the determination of halides, e.g.…”