Experimental and Computational Raman and SERS Study of Acid Blue 113

ABSTRACT The Acid Blue 113 dye (AB‐113) is widely employed in the textile industry due to its remarkable dyeing capabilities on wool, nylon, and silk, ensuring stability throughout the washing process. While most research has focused on its adsorption, removal, degradation, and discoloration, a gap exists regarding its vibrational characterization. In this study, AB‐113 was investigated through FT‐IR, Raman, and SERS spectroscopies, analyzed on the basis of DFT computational studies. The SERS spectra were calculated considering an Ag 8 cluster interacting with AB‐112 as a model for the dye on the Ag nanoparticle surface. The simulated Raman and SERS spectra showed good agreement with experimental spectra, and their vibrational assignments are consistent with analogous parts of the molecules documented in previous studies. Furthermore, we observed that the bands in the 1460–1370‐cm −1 range, assigned to vibrational modes of the azo group, had their relative intensity increased depending on the excitation wavelength, maximizing at 532 nm due to the resonance Raman effect. The SERS spectrum also showed higher intensity at excitation wavelengths of 532 and 632.8 nm due to resonance Raman effects of the dye; on the other hand, more significant changes in the relative intensities in the SERS spectrum due to the adsorption process were observed at nonresonance (λ 0 = 785 nm) conditions. The interaction between AB‐113 and AgNPs was inferred by comparing theoretical and experimental SERS spectra, which helped propose the interaction of the dye through a sulfonate group with the silver surface. Finally, it was demonstrated that AB‐113 can be detected by SERS down to a concentration of 1.0 × 10 −8 mol L −1 using wavelengths of 532 and 632.8 nm, reinforcing that this molecule could serve as a high‐performance probe molecule for SERS applications.