Structure and dynamics in liquid bismuth and Bin clusters: A density functional study

The s-p Nonhybrid Nature Causes Adaptive Superatomic States of Bismuth Clusters

We report a joint experimental and theoretical study on the stability and reactivity of Bin + (n=5-33) clusters. The alternating odd-even effect on the reaction rates of Bin + clusters with NO is observed, and Bi7 + finds the most inertness. First-principles calculation results reveal that the lowest energy structures of Bi6-9 + exhibit quasi-spherical geometry pertaining to the jellium shell model; however, the Bin + (n≥10) clusters adopt assembly structures. The prominent stability of Bi7 + is associated with its highly symmetric structure and superatomic states with a magic number of 34e closed shell. For the first time, we demonstrate that the unique s-p nonhybrid feature in bismuth rationalizes the stability of Bi6-9 + clusters within the jellium model, by filling the 6s electrons into the superatomic orbitals (forming "s-band"). Interestingly, the stability of 18e "s-band" coincides with the compact structure for Bin + at n≤9 but assembly structures for n≥10, showing an accommodation of the s electrons to the geometric structure. The atomic p-orbitals also allow to form superatomic orbitals at higher energy levels, contributing to the preferable structures of tridentate binding units. We illustrate the s-p nonhybrid nature accommodates the structure and superatomic states of bismuth clusters.

The chemical bond in solids-revisited

This article complements an earlier topical review of the chemical bond (Jones 2018J. Phys.: Condens. Matter30153001), starting in the mid-19th century and seen from the perspective of a condensed matter physicist. The discussion of applications focused on the structure and properties of phase change materials. We review here additional aspects of chemistry, particularly some that have raised interest recently in this context. Concepts such as 'electron-rich', 'electron-deficient (excess orbital)', 'hypervalent', 'three-centre', and 'metavalent' bonds, and 'multicentre hyperbonding' are now found in the condensed matter literature. They are surveyed here, as well as the bond in metals and the 'Peierls' distortion. What are these concepts, are they related, and are they sometimes new labels for established, but unfamiliar ideas? 'Half bonds' and 'fractional valencies' play a central role in this discussion. It is remarkable that they were introduced 100 years ago, but ignored or forgotten, and have needed to be rediscovered more than once.

The bismuth tetramer Bi4: the ν3 key to experimental observation

The spectroscopic identification of Bi₄ has been very elusive. Two constitutional Bi₄ isomers of T_d and C_2v symmetry are investigated and each is found to be a local energetic minimum.

Density functional study of structure and dynamics in liquid antimony and Sbn clusters

Density functional/molecular dynamics simulations have been performed on liquid antimony (588 atoms and six temperatures between 600 K and 1300 K) and on neutral Sb clusters with up to 14 atoms. We study structural patterns (coordination numbers, bond angles, and ring patterns, structure factors, pair distribution functions) and dynamical properties (vibration frequencies, diffusion constants, power spectra, dynamical structure factors, viscosity) and compare with available experimental results and with the results of our previous simulations on Bi. Three short covalent bonds characteristic of pnictogens are common in the clusters, and higher temperatures lead in the liquid to broader bond angle distributions, larger total cavity volumes, and weaker correlations between neighboring bond lengths. There are clear similarities between the properties of Sb and Bi aggregates.

Deep melting reveals liquid structural memory and anomalous ferromagnetism in bismuth

As an archetypal semimetal with complex and anisotropic Fermi surface and unusual electric properties (e.g., high electrical resistance, large magnetoresistance, and giant Hall effect), bismuth (Bi) has played a critical role in metal physics. In general, Bi displays diamagnetism with a high volumetric susceptibility ([Formula: see text]10^-4). Here, we report unusual ferromagnetism in bulk Bi samples recovered from a molten state at pressures of 1.4-2.5 GPa and temperatures above [Formula: see text]1,250 K. The ferromagnetism is associated with a surprising structural memory effect in the molten state. On heating, low-temperature Bi liquid (L) transforms to a more randomly disordered high-temperature liquid (L') around 1,250 K. By cooling from above 1,250 K, certain structural characteristics of liquid L' are preserved in L. Bi clusters with characteristics of the liquid L' motifs are further preserved through solidification into the Bi-II phase across the pressure-independent melting curve, which may be responsible for the observed ferromagnetism.