Probing the Geometric and Electronic Structures of the Monogadolinium Oxide GdO n-1/0 ( n = 1-4) Clusters

On the Precise and Continuous Regulation of the Superatomic and Spectroscopic Behaviors of the Quasi-Cubic W4C4 Cluster by the Oriented External Electric Field

Designing and realizing novel superatoms with controllable and tunable electronic properties is vital for their potential applications in cluster-assembly nanomaterials. Here, we investigated the effect of the oriented external electric field (OEEF) on the geometric and electronic structures as well as the spectroscopic properties of the quasi-cubic W₄C₄ cluster by utilizing the density functional theory (DFT) calculations. Compared with traditional models, the OEEF was observed to hold the special capability in continuously and precisely modulating the electronic properties of W₄C₄, that is, remarkably increasing its electron affinity (EA) (1.58 eV) to 5.61 eV under the 0.040 au OEEF (larger than any halogen atoms in the periodic table), which possesses the superhalogen behavior. Furthermore, the downward movement of the lowest unoccupied molecular orbital level of the cluster accompanied by the enhancement of the OEEF intensity was demonstrated to be the origin of the EA increment. Additionally, the photoelectron spectra (PES) of W₄C₄^- were also simulated under different OEEF intensities, where the PES peaks move to a higher energy area following the enhancement of the OEEF strength, exhibiting the blue-shift behavior. These findings observed here open a new avenue in conveniently and precisely adjusting the electronic properties of clusters, which will be beneficial for the rational design of superatoms or superatom-assembled nanomaterials under the external field.

Probing the geometric and electronic structures of the lanthanide oxide HoOn-1/0 (n = 1-3) clusters

The complex 4f and 5d orbits of lanthanide oxide clusters increases the complexity and difficulty in both theoretical and experimental research. Combining the photoelectron imaging spectroscopy and ab initio calculations, the structural and electronic properties of HoO^- were studied. The adiabatic detachment energy (ADE) and vertical detachment energy (VDE) of HoO^- have been measured to be 1.31(3) eV and 1.42(2) eV, respectively. To determine the vibrational structure and observed spectral bands in the photoelectron spectrum, Franck-Condon simulation of the ground-state transition for HoO^- has been performed. The fundamental frequency of ground-state HoO is estimated to be 893 ± 73 cm^-1. Density functional method (DFT) was used to study the neutral and anionic clusters of HoO_n^-1/0 (n = 1-3), and the most stable cluster structures were obtained. Based on the DFT calculations, the theoretical ADEs and VDEs of anionic HoO_n^- (n = 1-3) clusters were obtained and the photoelectron spectra (PES) of HoO_n^- (n = 1-3) clusters were simulated, which might stimulate further experimental investigations on the Ho oxide clusters. In addition, the corresponding molecular orbitals (MOs) were also discussed to reveal the interaction between Ho and O atoms. This study can help us to understand the chemical bonding in Ho-containing molecules and will provide some light in their surface chemistry and photochemistry investigation.

Revealing the effect of the oriented external electronic field on the superatom-polymeric Zr3O3 cluster: Superhalogen modulation and spectroscopic characteristics

Seeking novel strategies for designing superatoms is of significance for the potential applications in cluster-assembled nanomaterials. Herein, by employing the density functional theory (DFT) calculations, the effect of the oriented external electronic field (OEEF) on the electronic and photoelectron spectroscopic properties of the superatom-polymeric Zr₃O₃ cluster was explored. We present the evidence that the increment of the OEEF along all directions results in the remarkable enhancement of the electron affinity (EA) of Zr₃O₃, which turns it into superhalogen with an EA value of 4.02 eV under 0.020 au OEEF along +y direction. Strikingly, this EA value is larger than that of any halogen atoms in the periodic table. The downward shift of the electronic spectrum induced by the OEEF was confirmed to be the origin of the observed EA enhancement. Furthermore, the investigation of the OEEF's effect on the molecular orbitals (MOs) and photoelectron spectra (PES) of the cluster reveals that the OEEF could alter the electron distribution as well as promoting the blue shift of the PES without changing the spacings between different energetic levels. The OEEF highlighted here provides a new strategy in designing superatoms together with tuning their electronic and spectroscopic properties conveniently and precisely. We wish this finding could stimulate more efforts in designing novel superatoms or superatom-assembled materials from both theory and experiments.

Polymeric tungsten carbide nanoclusters: structural evolution, ligand modulation, and assembled nanomaterials

Seeking novel superatoms with tunable electronic and magnetic properties has attracted much interest due to their potential application in cluster assembly nanomaterials. By employing density functional theory (DFT) calculations, the recently observed superatomic WC cluster was adopted as the basic unit to construct larger polymeric clusters, namely (WC)_n (n = 2-7), and their structural evolution was explored to understand the growth pattern of these superatomic clusters into nanoscale materials. An unusual odd-even pattern in structural evolution was disclosed, in which the (WC)₂ unit is considered as the basic building block. Moreover, W₄C₄ is found to possess a cubic structure, based on which the CO and PH₃ ligands were attached to examine their ligation effects on W₄C₄. Theoretical results show that the electronic properties of W₄C₄ can be dramatically altered during the ligation process. Intriguingly, the continuous attachment of CO and PH₃ ligands strongly increases and decreases the electron affinities (EA) and ionization potentials (IP) of the ligated W₄C₄ clusters, respectively, leading to the formation of superhalogen and superalkali species with high magnetic moments. The observed ligand induced strategy highlighted here could serve as an effective way to tune the electronic and magnetic properties of clusters resulting in the formation of novel superatoms. Finally, studies on the geometrical and electronic structures of the W₄C₄ cluster solid unveil its special 3-D cubic honeycomb geometry and metallic properties with predominant contribution from the 5d of W, which may have potential applications in electro-catalysis.

Unveiling the electronic structures and ligation effect of the superatom-polymeric zirconium oxide clusters: a computational study

Discovering the non-noble ZrO cluster as an analog of the noble metal catalyst Pd is of significance toward designing functional materials with fine-tuned properties using the superatom concept. The effect of gradually assembling the ZrO superatomic unit on the electronic structures and chemical bonding of larger ZrO-polymeric clusters, however, is unclear. Herein, by using density functional theory (DFT) calculations, the lowest-energy structures and low-lying isomers of the (ZrO)n-/0 (n = 2-5) clusters were optimized, in which every O atom in these clusters tends to connect its adjacent two Zr atoms forming metal oxygen bridge bonds. Insights into the electronic characteristics of these clusters were obtained by analyzing their molecular orbitals (MOs) and density of states (DOS). More importantly, our studies on the CO (electron acceptor) and PH3 (electron donor) ligated Zr3O3 clusters unveil that the ligation process can substantially alter the electronic properties of the clusters by tuning the HOMO and LUMO states, which may have potential applications in photovoltaics. Strikingly, the successive attachment of PH3 on Zr3O3 dramatically lowers the adiabatic ionization potential (AIP) of the ligated clusters, resulting in the formation of stable superalkali clusters with large HOMO-LUMO gaps. Furthermore, the potential of constructing the superalkali Zr3O3(PH3)5 based 1-D cluster assembled material was also examined.