Computational characterisation of structure and metallicity in small neutral and singly-charged cadmium clusters

Abstract

Putative global minimum structures for neutral Cd N and singly charged Cd + N and Cd − N clusters in the small size regime up to N = 21 atoms are reported. A global optimization approach based on the basin hopping method and a Gupta potential fitted to cluster properties is employed to generate a diverse databank of trial structures, which are then re-optimized at the densityfunctional level of theory. Novel, previously unreported, structures are found for many sizes. Our results successfully reproduce and interpret the size-dependent stabilities known from mass spectrometry, and strongly suggest that experiments aimed at determining the relative stabilities of neutral cadmium clusters are really measuring cation stabilities. We provide an in-depth analysis of electronic structure and use it to explain the gradual emergence of metallic-like behaviour as the cluster size increases. † Electronic Supplementary Information (ESI) available: Atomic coordinates (in xyz format andÅ units) and point group symmetries for the Global Minimum structures reported in this paper. See

Variation of the optical properties with size and composition of small, isolated CdxSey+ clusters

“…All these structures exhibit a trigonal bipyramidal Cd 5 unit as main building block. Previously, lowest‐energy structures of Cd x + clusters were reported 27 . In our GO procedure we have found all the proposed Cd x + structures and additionally new ones with lower energy for x = 4, 5, 7, 8.…”

“…In our GO procedure we have found all the proposed Cd x + structures and additionally new ones with lower energy for x = 4, 5, 7, 8. The energetic stabilization of the new lowest energy structures are given in eV in brackets relative to the ones recently proposed: 27 Cd 4 + (0.14), Cd 5 + (0.17), Cd 7 + (0.14) and Cd 8 + (0.02). On the other hand, pure Se y + clusters for y = 3 already possess an angled geometry and larger species form ring structures as it is known for neutral Se clusters in which all selenium atoms are twofold coordinated 28,29 .…”

Thickness-dependent characteristics and oxidation of 2D-cadmium

“…Zhao calculated that Cd n clusters that have closed electronic shells demonstrate magic number behavior for some n , and the size dependence of ionization potentials converges towards the bulk limit. 17 While Alvarez et al showed that metallicity of Cd n clusters emerges as a result of sp-hybridization, 18 and a study by Kohaut et al revealed that such clusters do not show metallic properties up to n = 60. 19 Besides, Oyeniyi et al developed and used a method to calculate the electronic excitation energies and absorption spectra of zero dimensional Zn, Cd and S clusters.…”