Formation of cyanide compounds during preparation of gold surfaces evidenced by surface‐enhanced Raman spectroscopy

Abstract

We report surface‐enhanced Raman spectroscopy (SERS) measurements on nanostructured gold surfaces prepared using a primary vacuum sputtering technique. Even if no molecules have been deposited on the metallic surface, a clear Raman signal is observed. A very intense and sharp peak around 2,100 cm−1 together with low‐wavenumber modes are visible. The comparison between the experimental spectra and those obtained using density functional theory calculations confirms that these new modes are associated with the cyanide compound Au(CN)2−. This proves the high sensitivity of SERS for the chemical analysis of metallic surfaces. It also shows that the pollution should be carefully taken into account in SERS analysis. We also demonstrate that high power laser illumination transforms these toxic compounds into carbon species; this method can be used to clean SERS substrates.

Spectral fluctuation in SERS spectra of benzodiazepin molecules: The case of oxazepam

“…Numerical calculations and, in particular, DFT are essential for the interpretation of SERS spectra. [ 16,17 ] Those calculations have been carried out at the B3PW91/6‐31G* level of theory using the GAUSSIAN09 [ 18 ] suit of programs. We have calculated the structure of the isolated oxazepam molecule together with its set of harmonic frequencies.…”

Recent advances in linear and nonlinear Raman spectroscopy. Part XIII

“…They also demonstrated that high power laser illumination transforms these toxic compounds into carbon species, and this method can be used to clean SERS substrates. [42] Milan-Garces et al carried out a study of the chemical behaviour of croconic acid, the associated anionic species croconate, and their complexes with the transition metal Co (II) using SERS. [43] Odion and co-workers carried out inverse surface-enhanced spatially offset Raman spectroscopy through a monkey skull.…”

“…Merlen and co‐workers were able to follow the formation of cyanide compounds during the preparation of gold surfaces using SERS. They also demonstrated that high power laser illumination transforms these toxic compounds into carbon species, and this method can be used to clean SERS substrates . Milan‐Garces et al carried out a study of the chemical behaviour of croconic acid, the associated anionic species croconate, and their complexes with the transition metal Co (II) using SERS .…”

Raman spectra and DFT calculations of thiophenol molecules adsorbed on a gold surface

“…Since its discovery at the end of the 70s, SERS is considered as an extremely promising analytical method for the detection of low concentration chemical species. Its application covers a very broad field: the detection of drugs or illegal substances, 1 the analysis of pollutant molecules in water, [2][3][4] the identification of chemical species at the surface of metals, 5 the study of pigments in art or archeology, 6,7 and many others.…”