Identification of amphetamine as a stimulant drug by pristine and doped C₇₀ fullerenes: a DFT/TDDFT investigation

The density functional theory (DFT) was used to examine the electronic reactivity and sensitivity of a pristine, Si, and Al-doped fullerene C₇₀ with AM drug. AM drug has been shown to be physically absorbed by its N-head on the pristine C₇₀ with an adsorption energy of about - 1.09 kcal/mol and to have no impact on the electric conductivity of that cluster. The atom substitution of Si and Al for C atoms at C₇₀ significantly increases C₇₀ fullerene reactivity, with adsorption energy predictions of approximately - 31.09 and - 45.59 kcal/mol, respectively. The energy difference of LUMO and HOMO, i.e., Eg from C₇₀ fullerene, significantly affects AM drug. Significant LUMO destabilization in Al-C₇₀ by adsorption of the drug AM boosts the electrical conductivity of Al-C₇₀ while generating electric signals that are related to the environmental presence of AM drug. Hence, Al-doped C₇₀ is demonstrated to be an effective electronic AM drug sensor. In contrast to Si-C₇₀ fullerene, significant AM-drug adsorption effects on Fermi and Si-C₇₀ work functions make Si-C₇₀ an Ф-type candidate for AM drug sensor applications. The time-dependent theory of the functional density shows that the AM/Al-C₇₀ complex is steadily situated at a maximum peak of 784.15 nm.