INVESTIGADORES
MALDONADO Alejandro Fabian
artículos
Título:
Relativistic effects on the energetic stability of Pb5 clusters
Autor/es:
F. FERRARO; A. D. ZAPATA; A. F. MALDONADO
Revista:
THEORETICAL CHEMISTRY ACCOUNTS
Editorial:
SPRINGER
Referencias:
Lugar: Berlin; Año: 2020
ISSN:
1432-881X
Resumen:
In this work, we study isomers of small lead clusters with ve atoms, Pb 5 , at different levels of approximation namely ScalarRelativistic (SR), ScalarRelativistic plus SpinOrbit coupling interaction (SR+SO) and fourcomponent Dirac-Hartree-Fock (4c-DHF), in order to analyse the eects of Relativity in these heavy molecular systems. The exploration of Potential Energy Surface (PES) with a genetic algorithm produces four possible equilibrium structures, and we nd that when Relativity is included ata major level in calculations, the global minimum energy structure changes from S4 isomer with D 3h symmetry at SR level to S1 isomer with C 2 symmetry at 4c-DHF level; this change is related to modications in the electronic structure and geometric parameters. We explain this signicant result using two methodologies in order to analyse the electronic structure and strength of chemical bonds, like Energy Decom-position Analysis (EDA) and Quantum Theory Atoms In Molecules (QTAIM). On the one hand, in the framework of EDA, results at SR+SO level show signicant dierences on the steric and orbital interactions compared with SR ones, with which the S1 isomer is more stable than S4; this means that SO eects stabilize the interactions on S1 isomer more than S4. The HOMOLUMO gap also shows a drastic reduction dueto the SO eects on S4 isomer, while for the other systems remains unchanged. This result can be associated with the lower stability of S4 isomer with respect to the others when Relativity is included at a major level. On the other hand, in the framework of QTAIM, calculations with SR+SO scheme show the formation of two new critical points compared with SR for S1 isomer, which is reected in a greater stability of thissystem.