Systematic research on gallium atom-doped neutral small- and medium-sized gas-phase magnesium clusters: A DFT study of GaMgn (n=2–12) clusters

Abstract

Structure, stability, charge transfer, chemical bonding, and spectroscopic properties of Ga atom-doped neutral Mgn (n=2-12) clusters have been systematically investigated by CALYPSO and density functional theory. All cluster structures are based on "tetrahedral" and "yurt-like" growth except for GaMg2. The ground state isomer of GaMg with high symmetry strcture is predicted to be the best-fit candidate for the "magic" cluster because of its excellent stability. Natural bond orbital calculations reveal that Ga and Mg atoms play the role of electron acceptor and donor in all ground state isomers, while the orbitals in both Ga and Mg are sp-hybridized. Most importantly, chemical bonding studies based on atom-in-mole ular theory have shown that the lowest-energy state of GaMg4 is so special in that it is not only the critical size for the appearance of Mg-Mg covalent bonds but also the only cluster that has both Ga-Mg covalent and non-covalent bonds. Finally, theoretical calculations of IR and Raman spectra of all ground state isomers indicate that the spectra of these clusters are observable in the low-frequency band, and thus they can be identified by spectroscopic experiments. Furthermore, the bond heterogeneity of the Ga-Mg in the GaMg4 ground state isomer has also been specically investigated, includingfixed GaMg4 structure with Mg atoms added in different directions as well as ab initio molecular dynamics sampling at different temperatures.

DFT-Based Study of the Structure, Stability, and Spectral and Optical Properties of Gas-Phase NbMgn (n = 2–12) Clusters

“…In summary, our calculations show that in addition to the NbMg 2 clusters showing linear and planar structures, the structural growth of Nb atom-doped Mg n ( n = 3–12) clusters is based on the growth of tetrahedral and pentahedral structures, which can be regarded as two seed unit structures, as presented in Figure S1 of the Supporting Information. It is interesting to note that the spin multiplicity of the small-sized NbMg n ( n = 2–5) ground-state isomer is 6, while those of the ground-state isomers of BeMg n , GaMg n , , and other Mg-based clusters are mostly 2.…”

“…The 8-① isomer appears to be special because its upper part is pentahedral and its lower part is tetrahedral, so we can identify it as a transformation node size for the structural change of the NbMg n cluster. It is necessary to emphasize that this complex structure, which grows up in a pentahedral structure, sometimes presents a tower-like (such as BeMg 9 ) or yurt-like , structure. Interestingly, isomers 8-② and 8-③ have the similar quadrangular antiprism structures, which are the same as the structure of the lowest-energy isomers of the 4d-transition-metal atom X-doped Mg 8 host (X = Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, and Ag) .…”

“…Various spectral properties, such as IR, Raman, UV–vis, and photoelectron spectra, are powerful data to guide experimental verification. For example, these spectral values were calculated theoretically for magnesium-based clusters, − silicon-based clusters, , and boron-based clusters. , These studies, although they are mostly carried out theoretically and have no possibility of being experimentally confirmed in the short term, can, on the one hand, fill the database of atomic clusters and, on the other hand, they are basic scientific problems that must be clarified for people to understand the macroscopic structure of atoms aggregated into clusters to blocks. Therefore, the study of clusters with a wide range of material applicabilities, including their spectroscopic studies, is always favored by researchers.…”

Probing the effects of lithium doping on structures, properties, and stabilities of magnesium cluster anions

“…The magic numbers N = 4, 10, and 20 present in these clusters can be perfectly explained by using the spherical Jellium model. [21] Numerous binary clusters are accordingly found to have excellent properties by doping Mg clusters with foreign atoms, [22][23][24][25][26][27] such as magnetic superatoms T MMg 8 (T M = Fe, Co, Ni, and Tc), [28,29] efficient catalysts T MMg 55 (T M = Ti and Nb), [30] high stability cage BeMg 16 cluster, [31] and so on. To some extent, these experimental and theoretical results are significant for the enrichment of magnesium-based clusters.…”

Study of the hydrogen absorption behaviour of a “number-sensitive” Mg atom: ultra-high hydrogen storage in MgHn (n = 1–20) clusters

“…21 On the other hand, it also helps researchers understand more about the electronic structure, charge transfer and the nature of the chemical bonds between the atoms in these clusters. Taking the study of pure and metal-doped metal-atom clusters as an example, for instance, GeMgAu n (n = 1-12), 22 GaMg n (n = 2-12), 23 Be m Mg n (m = 1,2; n = 1-12), 24,25 and Mg n (n = 2-56), 26 have shown that in small-sized metal-atom clusters, the critical size of the metal bonding properties is still difficult to nd directly. However, the search for the size of chemical bonding phase transitions in clusters of metal atoms is of great scientic interest and has been one of the most important objects of research in the eld of cluster studies.…”