A DFT study of the adsorption and surface enhanced Raman spectroscopy of pyridine on Au20, Ag20, and bimetallic Ag8Au12 clusters

SERS-Based Sensor Using Subnanometric Copper–Silver Mixed Clusters Ag(8–n)Cun (n = 0–8) for Pyridine: A DFT Study

“…In all other cases, the electron and hole are both located on the metallic clusters, making the transition local excitation (LE). This intracluster excitation of the lowest-lying excitation stated by CAM-B3LYP has been previously reported by Seuret-Hernandez et al 20 The atomic contribution to holes and electrons for the lowest excited state (S 1 ) is provided in Table S7 S8, SI) that helps to define the excitation nature as charge transfer is also computed. A charge-transfer excitation is estimated with a Δr value higher than 2 Å, and a local excitation is considered with a Δr value smaller than 2 Å.…”

“…Similar observations on the performance of the pyramidal Ag 20 cluster were also recognized in the study of chlorpyrifos pesticide. 6 An excellent agreement between experimental and modeling results was also reported on the SERS spectra study of thiram fungicide adsorbed on silver nanoparticles when using the Ag 20 PBE/cc-pVDZ-PP//PBE-cc-pVDZ level of theory. 7 Takenaka et al evaluated the DFT calculations with the dispersion interaction for SERS spectra modeling 2,2′-bipyridyl adsorbed on pyramidal Au 20 , Ag 20 , and Au 10 Ag 10 mixed clusters.…”

“…Recently, Seuret-Hernańdez and Morera-Boado theoretically analyzed in detail the SERS spectra of Py adsorbed on the Ag 10 Cu 10 tetrahedral (T d ) clusters via two binding positions: vertex (V) and surface (S). 20 As a result, the static SERS response for Cu−Py−V complexes is 5 to 10 times greater than that for Ag−Py−V complexes and up to 28 times greater than that for Py−S complexes. The Raman spectra of the Ag−Py−vertex or surface bimetallic clusters are enhanced compared with monometallic clusters, indicating that adding Cu atoms can improve the SERS enhancement of the Ag 20 T d cluster.…”

Structural Growth Pattern, Electronic Configurations, and Spectral and Thermochemistry Properties of ZrSnn0/–/2– (n = 4–17) Nanoscale Compounds: A Systematic Study Using Density Functional Theory

“…The “substitution geometries” was the second approach, used to replace one Sn atom in the Sn n +1 compound with the Zr atom. The third approach that was executed selects the configurations that have already been published in the previous literature as supplements. − ,− For the second phase, these initial isomers were then further optimized at PBE0, B3LYP, , and CAM-B3LYP functionals, respectively, which provided reliable results. − Considering the high computational costs and accuracy, − we chose the triple-ζ LANL2TZ , basis set for the Zr atom, which is provided with a quasi-relativistic effective core potential, and the cc-pVTZ-PP , basis set for the Sn atom, which is provided with a relativistic effective core pseudopotential. Symmetry constraints were not presented during this process.…”

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

“…In addition, due to its limited size, the metallic cluster is far to mimic real metallic surfaces. 29 To address this important question, we focused our study on standard DFT calculations with a large metallic surface. We deliberately choose a simple method giving a good compromise between efficiency, simplicity and calculation costs.…”