Absorption wavelength (TD-DFT) and adsorption of metal chalcogen clusters with methyl nicotinate: Structural, electronic, IRI, SERS, pharmacological and antiviral studies (HIV and omicron).

The DFT B3LYP-LAND2DZ technique is used to examine interactions of Methyl nicotinate with copper selenide and zinc selenide clusters. The existence of reactive sites is determined using ESP maps and Fukui data. The energy variations between HOMO and LUMO are utilised to calculate various energy parameters. The Atoms in Molecules and ELF (Electron Localisation Function) maps are employed to investigate the topology of the molecule. The Interaction Region Indicator is used to determine the existence of non-covalent zones in the molecule. The UV-Vis spectrum using the TD-DFT method and DOS graphs are used to obtain the theoretical determination of electronic transition and properties. Structural analysis of the compound is obtained using theoretical IR spectra. To explore the adsorption of copper selenide and zinc selenide clusters on the Methyl nicotinate, the adsorption energy and theoretical SERS spectra are employed. Furthermore, pharmacological investigations are carried out to confirm the drug's non-toxicity. The compound's antiviral efficacy against HIV and Omicron is demonstrated via protein-ligand docking.