Asymmetric Hybridization Orbitals at the Charged Interface Initiates New Surface Reactions: A Quantum Mechanics Exploration

摘要

Although the first report of Hofmeister effects is more than 130 years old, the origins of the Hofmeister series remain debated. In this study, quantum mechanics (QM) analyses, dispersion-corrected p-DFT calculations, and dynamic light scattering (DLS) determinations are combined with the aim to unravel such a scientific basis. QM analyses show that asymmetric hybridization occurs for the outer-shell nsnp(z) orbitals at charged interfaces, and the asymmetric spz hybridization further initiates two unique processes for the interfacial ions: unusual polarization with a greatly enlarged polarizability and a new type covalent bonding of surface reactions with the asymmetric spz hybridization. The asymmetric hybridization theory is then applied and verified by surface reactions of K+ and Na+ with the charged montmorillonite surface. As predicted by QM analyses, p-DFT calculations show that, under no or low electric fields, the covalent bonding does not exist for both Na+ and K+, while under strong electric fields, covalent bonding is produced for K+ with surface-O atoms but remains absent for Na+. Also, as predicted by QM analyses, the DLS results confirm that the interfacial Na+ reactions are governed by two forces, as Coulomb interaction and unusual polarization, while in addition to these two forces (unusual polarization of K+ is 2.067 times as that of Na+), covalent bonding emerges for the interfacial and plays a dominant role. This study provides new scientific bases of Hofmeister effects at the subatomic level, which is of critical importance in both physical and biological systems.