Atomic bonding in equilibrium single-component melts. The cases of arsenic, antimony and bismuth

Abstract

In liquid pnictogens, quasi-stable structures can be formed near melting temperature. The nature of their stability does not have the unified point of view. In the present work, the task of determining the degree of atomic bonding in these structures is solved using the Crystal Orbital Hamilton Population (COHP) method. The original results of ab-initio simulation of arsenic, antimony and bismuth melts near their melting temperatures are used. It is shown that the features of the electron interaction at the level of $p$-orbitals determine the characteristic bond lengths and angles between atoms. It has been established that the stability of structures decreases according to a power law with an increase in the atomic mass of a chemical element and the number of atoms in the structure. The obtained results clarify the understanding the mechanisms of formation of quasi-stable structures in pnictogen melts from first principles.