A DFT Investigation of Surface‐Enhanced Raman Scattering of Adenine and 2′‐Deoxyadenosine 5′‐Monophosphate on Ag₂₀ Nanoclusters

Abstract

We present a detailed analysis of the surface-enhanced Raman scattering (SERS) of adenine and 2'-deoxyadenosine 5'-monophosphate (dAMP) adsorbed on an Ag(20) cluster by using density functional theory. Calculated Raman spectra show that spectral features of all complexes depend greatly on adsorption sites of adenine and dAMP. The complexes consisting of adenine adsorbed on the Ag(20) cluster through N3 reproduce the measured SERS spectra in silver colloids, and thus demonstrated that adenine interacts with the silver surface via N3. We also investigate the SERS spectrum of adenine at the junction between two Ag(20) clusters and demonstrate that adenine can bind to the clusters through N3 and the external amino group, while dAMP can be adsorbed on the cluster in an end-on orientation with the ribose and phosphate groups near to or away from the silver cluster. In contrast to the adenine-Ag(20) complexes, the dAMP-Ag(20) complexes produce new and strong bands in the low- or high-wavenumber region of the Raman spectra, due to vibrations of the ribose and phosphate groups. Furthermore, the spectrum of dAMP bound to the Ag(20) cluster via N7 approaches the experimental SERS spectra on silver colloids.

Surface enhanced Raman scattering of melamine on silver substrate: An experimental and DFT study

“…It is reported that SERS enhancements have been observed up to the power of 15 in single molecule experiments. [2] It is generally accepted that SERS effect is interpreted by electromagnetic and chemical enhancement. Electromagnetic enhancement arises from enhanced electric fields at the surface of particles due to plasmon resonance excitation.…”

Quantum chemical study of the electronic properties of an Iridium-based photosensitizer bound to medium-sized silver clusters

“…[40], except tetrahedral A g20 which had been studied before in Refs. [41][42][43]. Binding energies have been obtained including the counterpoise method to correct for the basis set superposition error (BSSE) [44,45].…”

Tailored Rh surface facilitates, enhancement of Raman scattering in trimetallic AuPt core/Rh shell composites: Experimental and theoretical evidences

“…This interaction can be analyzed by means of vibrational spectroscopy because it provides more specific information of the adsorbate. However, the ordinary Raman spectroscopy is basically unable to identify the properties of adsorbed organic and bio-molecules because of its low scattering intensity [14]. This inconvenience can be effectively overcome by resorting to surface-enhanced Raman spectroscopy (SERS) [15,16], in which, ordinary weak Raman scattering can be significantly enhanced when there is chemical adsorption of the analyte molecule on the surface of new metals [14].…”

“…However, the ordinary Raman spectroscopy is basically unable to identify the properties of adsorbed organic and bio-molecules because of its low scattering intensity [14]. This inconvenience can be effectively overcome by resorting to surface-enhanced Raman spectroscopy (SERS) [15,16], in which, ordinary weak Raman scattering can be significantly enhanced when there is chemical adsorption of the analyte molecule on the surface of new metals [14]. SERS is a phenomenon in which the scattering cross sections of probe molecules adsorbed on the surface of the metal is increased [17][18][19][20].…”

“…SERS is a phenomenon in which the scattering cross sections of probe molecules adsorbed on the surface of the metal is increased [17][18][19][20]. Basically, this SERS enhancement is originating from electromagnetic (EM) and chemical enhancement (CE) mechanism [14,21]. In recent years, SERS has become a sensitive spectroscopic technique for studying the chemisorption of probe molecules on the surface of nanometer sized metallic colloidal nanoparticles.…”