Fully relativistic study of polyatomic closed shell E121X3 (X = F, Cl, Br) molecules: effects of Gaunt interaction, relativistic effects and advantages of an exact-two component (X2C) hamiltonian

• Published in: Journal of molecular modeling 2021-09, Vol.27 (9), p.262-262, Article 262
• Main Authors: Pinheiro, Alan Sena, Gargano, Ricardo, Santos, Paulo Henrique Gomes dos, de Macedo, Luiz Guilherme Machado
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Computer Appl. in Life Sciences; Computer Applications in Chemistry; Density functional theory; Mathematical analysis; Molecular Medicine; Original Paper; Relativistic effects; Theoretical and Computational Chemistry; VIII Symposium on Electronic Structure and Molecular Dynamics – VIII SeedMol
• ISSN: 1610-2940; 0948-5023
• DOI: 10.1007/s00894-021-04861-7

In this study, all electron relativistic calculations with 4-component Dirac–Coulomb–Breit (DCB), 4-component Dirac–Coulomb (DC), Dyall’s spin-free Dirac–Coulomb (SFDC), exact two-component (X2C) and Levy–Leblond non-relativistic hamiltonians calculations were performed in polyatomic closed shell E121X 3 (X = F, Cl, Br) within density functional theory (DFT) with hybrid functional B3LYP, where E121 is the superheavy element (SHE) with Z = 121. The aims of this study were to investigate relativistic effects in polyatomic E121X 3 (X = F, Cl, Br) and verify the importance of Gaunt effects. The results demonstrate that although the effect of Gaunt interaction is small on change equilibrium bond lengths and bonding, it is important to obtain reliable vibrational frequencies. Moreover, it is possible to use the X2C spin-free hamiltonian to lower computational costs in a fully relativistic investigation of polyatomics including the SHE of the 8th period. Finally, a comparison between electron localization function (ELF) analysis and Mulliken population analysis suggests bonding similarity between LaBr 3 and E121Br 3 . Graphical Abstract Relativistic 4-Component calculations suggest bond similarity between LaBr 3 and E121Br 3 .