Outstanding NLO response of thermodynamically stable single and multiple alkaline earth metals doped C-20 fullerene

In the current study, the NLO response of single and multi-doped M@C-20 (M = Be, Mg and Ca) fullerenes is investigated. Electronic and NLO properties of C-20 fullerene are enhanced with increasing number of doped metal atoms. Doping of single and multi-atoms on/in C-20 fullerene significantly reduces the HOMO-LUMO gap of C-20 fullerene. Density of state (DOS) analysis illustrates generation of new states which are responsible for decrease in H-L gap. Ca-5@C-20 complex has the lowest HOMO -> LUMO of 1.40 eV and strong interaction energy of -99.02 kcal mol(-1). In all newly designed complexes, charge is transferred from metal to C-20 fullerene. The largest first hyperpolarizability of 6.5 x 10(7) au is observed for Ca-5@C-20 complex. The hyperpolarizability values are also rationalized through two-level model analysis. This study will promote research to design nanomaterials with enhanced electronic and optical properties. (C) 2020 Elsevier B.V. All rights reserved.