Formation of positive cluster ions Li(n) Br (n = 2-7) and ionization energies studied by thermal ionization mass spectrometry

Recent Progress on the Design, Characterization, and Application of Superalkalis

Superalkalis are clusters or molecules featuring lower ionization energies (IEs) than that of cesium atoms, and thus exhibit excellent reducing properties. Such special species have great potential to be used in the synthesis of unusual charge-transfer salts and cluster-assembled nanomaterials with tailored properties, in the reduction of carbon dioxide, or as hydrogen storage materials and noble-gas-trapping agents, etc. In this regard, ongoing efforts have been devoted to designing and characterizing superalkalis of new types. The recent progress on the study of superalkalis in terms of theoretical design, characterization, and potential application is summarized in this minireview. We hope this review will not only provide a broad overview of this research field, but also highlight the prospect of further extending the experimental synthesis and practical application of superalkalis.

Structure and stability of small lithium-chloride LinClm(0,1+) (n ≥ m, n = 1–6, m = 1–3) clusters

Detailed theoretical investigations along with the experimental observations of new small chlorine-doped lithium clusters are presented.

First-principle investigation on growth patterns and properties of cobalt-doped lithium nanoclusters

A systematic theoretical investigation on cobalt lithium clusters LinCo [1-12] was performed with a DFT approach. The location of global minima and structural evolution were carried out using the partical swarm optimization method. Li6Co is the transition structure in going from low-coordinated structures to three-dimensional torispherical structures with a cobalt atom enclosed by lithium atoms. Maxima of ∆2 E and E b for LinCo were found at n = 3, 6, 8, 10, indicating that these clusters possess higher relative stability than their neighbors. In comparison with small clusters, n = 1-6, the greater electron transfer from Li-2s to Co-3d within cage-like clusters LinCo (n = 7-12) strengthens the bonding effect between Lin and Co, which is reflected in the Wiberg bond index of Co and atomic binding energy analysis. AdNDP analysis verified the presence of both Lewis bonding elements (1c-2e objects) and delocalized bonding elements (6c-2e, 9c-2e and 10c-2e bonds). It is hoped that this theoretical work will provide favorable information to help understand the influence of dopant transition metal atoms on the properties of lithium-based materials.

Study of small chlorine-doped potassium clusters by thermal ionization mass spectrometry

The theoretical calculations have predicted that nonmetal-doped potassium clusters can be used in the synthesis of a new class of charge-transfer salts which can be considered as potential building blocks for the assembly of novel nanostructured material. In this work, K(n)Cl (n = 2-6) and K(n)Cl(n-1) (n = 3 and 4) clusters were produced by vaporization of a solid potassium chloride salt in a thermal ionization mass spectrometry. The ionization energies (IEs) were measured, and found to be 3.64 ± 0.20 eV for K(2)Cl, 3.67 ± 0.20 eV for K(3)Cl, 3.62 ± 0.20 eV for K(4)Cl, 3.57 ± 0.20 eV for K(5)Cl, 3.69 ± 0.20 eV for K(6)Cl, 3.71 ± 0.20 eV for K(3)Cl(2) and 3.72 ± 0.20 eV for K(4)Cl(3). The K(n)Cl(+) (n = 3-6) clusters were detected for the first time in a cluster beam generated by the thermal ionization source of modified design. Also, this work is the first to report experimentally obtained values of IEs for K(n)Cl(+) (n = 3-6) and K(n)Cl(n-1) (+) (n = 3 and 4) clusters. The ionization energies for K(n)Cl(+) and K(n)Cl(n-1) (+) clusters are much lower than the 4.34 eV of the potassium atom; hence, these clusters should be classified as 'superalkali' species.