Excitational, vibrational, and rotational temperatures in Nd:YAG and XeCl Laser-Induced plasmas

Evolution of Laser Plume upon Graphite Ablation in Vacuum and Nitrogen

“…The spectra of C and ë + atomic lines were observed in [9][10][11] but did not appear in our experiments. This difference may be explained by the fact that laser radiation at shorter wavelengths (248, 266, 308 nm) creating more severe excitation conditions was used for ablation in the cited works [9][10][11]. In our experiment when ablation takes place under relatively milder conditions ( λ = 532 nm), the direct vaporization of a large amount of C n carbon clusters, including C 2 , is possible.…”

Chemical processes in the atmospheric pressure plasma treatment of benzene

“…The presence of CN bonds in the discharge has been further observed by OES measurements by detecting the CN radical emission from the discharge. This radical shows extensive vibrational excitation even at atmospheric pressure and this can be explained either by energy transfer from the nitrogen triplet metastable state19 or by cleavage of CN groups from the polymeric film deposited on the discharge walls 20–23. These experimental findings suggest that the polymeric fraction of the deposit is composed of tholins, whose formation in the plasma treatment of hydrocarbon‐N 2 gas mixtures has already been reported 24, 25.…”

“…In ref.,38 in a DC discharge with graphite electrodes operated in nitrogen at about 1 mbar, high resolution spectra revealed a large excitation of CN(B) state with T rot = T vib ≥ 10 000 K. This was attributed to the production of CN radical species in exothermic reactions of metastable nitrogen atoms (P,D) with C atoms of the graphite surface, and the CN created in this way was identified as the precursor of CNx layers deposited on the walls. High vibrational temperatures were also found in plasmas produced by laser interaction with a graphite substrate at pressures below 1 Torr 20–22. In ref.,23 in a RF discharge fed with a mixture of acetylene, nitrogen and helium, dynamic actinometry revealed that part of the CN radicals producing the violet system emission came from reactions on the polymer surface formed on the discharge walls.…”

Burst Mode Q:switched Laser Pulses for Plasma Excitation in LIBS Analysis

“…LIBS is not a new technique: firsts laser-induced breakdown studies go back to the early 1960s and important application studies date from the 1980s with the work of Radziemski (Tognoni et al, 2002). A comprehensive review of LIBS development and applications through the mid-1990s was produced by Rusak et al(Rusak et al, 1997). The technique has many attributes that make it an attractive tool for chemical analysis, particularly as regards its potential as a field-portable sensor for geochemical analysis.…”