Regular Article

DFT calculations of the structures, electronic and spectral properties for Fe_nS_m (2 ≤ n + m ≤ 5) clusters

School of Physical Science and Technology, Southwest Jiaotong University, Key Laboratory of Advanced Technology of Materials (Ministry of Education), Chengdu 610031, P.R. China

^a e-mail: hongyanw@swjtu.edu.cn

Received: 20 November 2018
Received in final form: 31 December 2018
Published online: 21 March 2019

Abstract

The geometric structures, electronic and magnetic properties of the Fe_nS_m (2 ≤ n + m ≤ 5) small clusters are investigated using the density functional theory (DFT) method. The relative stability and chemical activity are analyzed based on the averaged atomization energy (E_a), energy gap (E_g), vertical electron affinity (VEA) and vertical ionization potentials (VIP) for the most stable Fe_nS_m (2 ≤ n + m ≤ 5) clusters. Fe₂S₃ and Fe₃S₂ clusters are expected to have the highest and the lowest energy gaps, corresponding to the highest chemical stability and highest chemical activity, respectively. The total magnetic moments of FeS_m (1 ≤ m ≤ 4) clusters are 4.0 μ_B, mainly attributed to Fe atoms except for FeS₃. Meanwhile the infrared vibrational spectra and photoelectron spectra are simulated to identify Fe_nS_m (2 ≤ n + m ≤ 5) clusters.