Perspective of Zn3O3 ring cluster via density functional theory

Abstract

ZnO is well known for its optical properties and broad application. Although it has been investigated extensively, information regarding Zn3O3 clusters in the form of a ring is insufficient. This paper discusses the extraction of a ZnO ring as a Zn3O3 cluster comprising three molecules obtained from a 2 × 2 × 2 zincite supercell and its optimized normal, cationic, and anionic forms under the density functional theory framework. Its geometric and electronic structures as well as electronically excited states are investigated based on electronic spectra. Furthermore, the density of states, transition densities of molecular orbitals, highest and lowest occupied molecular orbitals, lowest unoccupied molecular orbitals, gap energies, binding energies, ionization potential, electron affinity, and quantum descriptors are investigated. Significant changes in the ultraviolet (UV)–visible absorption spectra are reported based on time-dependent density functional theory. Weak interactions by non-covalent interactions in Zn3O3 are investigated for the first time in this study; variations in the electrostatic potential are also discussed. The stable form ring and its formation are investigated using thermodynamic potentials U, H, and G (with additional parameters such as zero-point energy and entropy), which are obtained through frequency optimization. The rings investigated from the Zn3O3 cluster suggest some possibilities, such as the tuning of UV to visible light absorption.