- - - Young Researchers and Elite Club, Yadegar-e-Imam Khomeini (RAH) Shahr-e-Rey Branch, Islamic Azad University, Tehran, Iran
- - - College of Health Sciences, University of Human Development, Sulaimaniyah, Kurdistan region of Iraq

In this paper, the detection of alprazolam by fullerene (C20) was studied by infra-red (IR), frontier molecular orbital (FMO) and natural bond orbital (NBO) computations. All of the computations were done by density functional theory method in the B3LYP/6-31G (d) level of theory. The calculated adsorption energies, Gibbs free energy changes and thermodynamic constants showed alprazolam adsorption is experimentally possible, spontaneous and irreversible. The calculated values of enthalpy changes and specific heat capacity demonstrated AP interaction with fullerene is exothermic and C20 can be used as a recognition element for the construction of a new thermal sensor for detection of alprazolam. The DOS spectrums showed the bandgap of fullerene decreased from 7.190 eV to 4.460 eV (%-37.9) in the alprazolam adsorption process and this nanostructure is a good electroactive sensing material for development of novel electrochemical sensors for alprazolam determination. Some important structural parameters including chemical hardness, chemical potential, electrophilicity, maximum charge capacity and the dipole moment of alprazolam in the adsorption process was also investigated.

Alprazolam, Adsorption, Density functional theory, Fullerene, Detection