Study of the Chemisorption and Sensing Performances of the Phenytoin Molecule onto the Gan (n = 3–6), Be12O12, and GaBe11O12 Clusters: DFT, DOS, ELF, QTAIM and Solvent Effects

The electronic characteristics of the Ga_n (n = 3–6), Be₁₂O₁₂, and GaBe₁₁O₁₂ clusters were examined by applying the DFT calculations with the B3LYP-D3/6-31G(d, p) method. The sensing performances of these clusters to the phenytoin (Phy) molecule were also evaluated in gas and water phases. The results show the adsorption of the Phy molecule over the Ga_n and Be₁₂O₁₂ clusters was viewed as a great chemical adsorption with E_ads which vary from –1.120 to –1.602 eV. While the interaction between the Phy molecule and the surface of the GaBe₁₁O₁₂ fullerene is considered as a moderate chemisorption. Due to the strong interaction between the adsorbent and the adsorbate, the energy gaps of the Ga_n, Be₁₂O₁₂, and GaBe₁₁O₁₂ clusters were significantly altered after the adsorption process, thus leading to a high sensitivity towards the chemisorbed molecule. The presence of water led to a little bit reduction in the adsorption energy of Phy molecule onto the clusters compared with the values observed in the gas phase, while maintaining their high-sensing performances. The comparison of the recovery time of the three types of clusters studied revealed that the Ga_n (n = 4, 5, and 6) and Be₁₂O₁₂ clusters possess a long recovery time, rendering them inappropriate nanomaterials to build regenerable biosensors for the Phy molecule detection, whereas the Ga₃ and GaBe₁₁O₁₂ clusters displayed a short recovery time (8.3 s and 5.7 × 10^–3 s), making them highly efficient nanosensors for capturing the Phy molecule in an aqueous solution.