DOI: 10.1016/j.matchemphys.2019.02.081

ABSTRACT

The electronic and optical properties of magnesium and aluminum hydride nanoparticles (NPs) have been examined using density functional theory (DFT) and time dependent DFT (TD-DFT). The absorption spectra (AS) of small size NPs obtained from selected functionals have been compared with high accuracy results from the equation-of-motion coupled-cluster with single and double excitations (EOM-CCSD) method. The comparison showed that the ASs from the CAM-B3LYP functional were in closer agreement with EOM-CCSD results. All calculations for NPs of larger sizes were performed using CAM-B3LYP. We show that the optical gap varies from 0.2 up to 5.5 eV for MgnHm, and from 1.0 up to 7 eV for Al_nH_m. The variation of the OG depends on two factors: the number of electrons in each NP (NPS with even number of electrons have higher OG), and the number of hydrogen atoms with the fully hydrogenated NPs (Mg_nH_2n and Al_nH_3n) having the highest OGs. That type of NPs show promise for applications such as quantum dots, e.g. solar cells, light emitting diodes and biolabeling.