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Laser-induced breakdown spectroscopy (LIBS) was used for the characterization of the main components of the surface residual dirt produced in cold-rolled steel plates as a consequence of the manufacturing stages. At laser fluences between 0.05 J/cm2< F< 0.30 J/cm2, dirt ablation takes place without any contribution from the substrate. Results show that the main components of the dirt are fine particles of Fe mostly homogeneously distributed in a thin layer of grease and soaps. In the primary stages of the manufacturing process carbon residuals can also be found. By measuring light emission from the λ = 495.9 nm line of Fe(I) after laser ablation, we developed a real-time on-line method for the determination of the concentration of iron particles present in the surface dirt. The obtained results open new possibilities in the design of real-time instruments for industrial applications as a quality control of products and processes.

The photophysical behaviour of 1-nitrocarbazol and 3-nitrocarbazol in different organic solvents has been studied by using spectroscopic, luminescence and photoacoustic techniques. Absorption spectra and triplet state transient spectra were recorded and formation quantum yields and lifetimes determined. Phosphorescence emission at 77 K and laser induced luminescence in acetonitrile solution at 298 K for the nitrocarbazoles were studied. Results are discussed in terms of the optimized structure of 1-nitrocarbazole and 3-nitrocarbazole and compared with that of carbazole. The nitro group attached to the carbazole moiety induces important changes in the photophysical behavior of those compounds.

The photophysical behaviour of 1-nitrocarbazol and 3-nitrocarbazol in different organic solvents has been studied by using spectroscopic, luminescence and photoacoustic techniques. Absorption spectra and triplet state transient spectra were recorded and formation quantum yields and lifetimes determined. Phosphorescence emission at 77 K and laser induced luminescence in acetonitrile solution at 298 K for the nitrocarbazoles were studied. Results are discussed in terms of the optimized structure of 1-nitrocarbazole and 3-nitrocarbazole and compared with that of carbazole. The nitro group attached to the carbazole moiety induces important changes in the photophysical behavior of those compounds.

The photophysical behaviour of 1-nitrocarbazol and 3-nitrocarbazol in different organic solvents has been studied by using spectroscopic, luminescence and photoacoustic techniques. Absorption spectra and triplet state transient spectra were recorded and formation quantum yields and lifetimes determined. Phosphorescence emission at 77 K and laser induced luminescence in acetonitrile solution at 298 K for the nitrocarbazoles were studied. Results are discussed in terms of the optimized structure of 1-nitrocarbazole and 3-nitrocarbazole and compared with that of carbazole. The nitro group attached to the carbazole moiety induces important changes in the photophysical behavior of those compounds.

Deactivation processes of Rhodamine B (RB) in water and interacting with silver sols were studied by using conventional fluorescence, laser-induced fluorescence, and pulsed laser photoacoustics. Results showed that the emission efficiencies, absorption cross sections, and nonradiative deactivation pathway of RB interacting with silver spheroids of different sizes are comparable to those obtained for the dye in aqueous solutions.

Bovine serum albumin, as well as other proteins, produces optoacoustic signals when excited with a laser pulse at wavelengths from 532 to 670 nm, a region where these proteins have no reported absorption. Signals from filtered solutions (obtained at low fluences) exhibited a linear dependence on laser energy and on protein concentration. Hence, they are attributed to radiationless deactivation following weak absorption in the visible region. Molar absorption coefficients calculated for different proteins showed a similar wavelength dependence, albeit with different absolute values—differences that could not be simply correlated to the content of known protein chromophores, such as tryptophan, tyrosine, and peptide bond. Moreover, at 532 nm, such chromophores produced optoacoustic signals only slightly higher than those from the buffer. On the other hand, a synthetic copolymer of tryptophan and lysine produced signals of a magnitude comparable to those from the proteins. Therefore, the weak absorption detected by laser-induced optoacoustics should be attributed to a not-yet-well-established feature of the structure of the protein, probably related to charge transfer interactions between different amino acids. Regardless of their origin, these signals must be taken into account when chromophoric prosthetic groups are studied with the use of laser-induced optoacoustic spectroscopy.

•LIBS has advantages for the analysis of unique pieces of heritage value.•The composition of eight archaeological metal objects from Patagonia was determined.•The compositional analysis allowed to discuss the possible origin of archaeological pieces.