A systematic DFT study of arsenic doped iron cluster AsFe n (n = 1–4)

Abstract The research on metallic clusters in relevance to its far-reaching involvement in the high technology sector, solid-state physics and catalysis is an interesting and significant field of study. In this report, the investigation of arsenic doped iron cluster, AsFe n (n = 1–4) aided by conceptual density functional theory (CDFT) method has been performed. CDFT based global descriptors-mainly HOMO–LUMO energy gap and other parameters of these clusters are worked out. Obtained data shows that band energy gap varies in the magnitude of 1.451–3.138 eV. Uppermost magnitude of HOMO–LUMO energy gap i.e. 3.138 eV is observed for AsFe while AsFe4 show the smallest energy gap. It is noted that band gap of these systems decreases with increase in the cluster size, ‘n’. Direct association concerning both parameters HOMO–LUMO energy gap and molecular hardness of AsFe n clusters have been found. It indicates that among the studied compound AsFe is the most stable system whereas AsFe4 is the least stable. Dipole moment of the clusters is observed in the variation of 2.303 Debye to 3.853 Debye, signifying that the bond within the clusters is ionic in nature. The computed bond length between Fe–Fe in AsFe n is in agreement with the experimental data.