Relativistic effects on inversion barriers of pyramidal group 15 hydrides

Author(s)

Santiago, Regis T. ^[1] ; Haiduke, Roberto L. A. ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Quim Sao Carlos, Dept Quim & Fis Mol, Av Trabalhador Sao Carlense, 400 CP 780, BR-13560970 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: International Journal of Quantum Chemistry; v. 118, n. 14 JUL 15 2018.
• Web of Science Citations: 0

Abstract

Quantum chemistry is an important tool for determining general molecular properties, although relativistic corrections are usually required for systems containing heavy and super heavy elements. Non-relativistic along with relativistic two- and four-component electronic structure calculations done with the CCSD-T method and the new RPF-4Z basis set have therefore been applied for determining inversion barriers, corresponding to the change from a pyramidal (C-3v) ground-state structure to the trigonal planar (D-3h) transition state, TS, of group 15 hydrides, XH3 (X= N, P, As, Sb, and Bi). The ground-state structure of the McH(3) molecule, which contains the super heavy element Moscovium, is also predicted as pyramidal (C-3v), with an atomization energy of 90.8 kcal mol(-1). However, although non-relativistic calculations still provided a D-3h planar TS for McH(3), four-component relativistic calculations based on single-reference wave functions are unable to elucidate the definitive TS geometry in this case. Hence, the results show that relativistic effects are crucial for this barrier determination in those hydrides containing Bi and Mc. Moreover, while the scalar relativistic effects predominate, increasing barrier heights by as much as 17.6 kcal mol(-1) (32%) in BiH3, the spin-orbit coupling cannot be disregarded in those hydrides containing the heaviest group 15 elements, decreasing the barrier by 2.5 kcal mol(-1) (4.5%) in this same molecule. (AU)

• FAPESP's process: 14/23714-1 - Electronic structure relativistic calculations for evaluation of new prolapse-free basis sets
• Grantee: Roberto Luiz Andrade Haiduke
• Support type: Regular Research Grants
• FAPESP's process: 10/18743-1 - Employment of multipoles from the quantum theory of atoms in molecules and kinetic studies in systems found in the interstellar medium
• Grantee: Roberto Luiz Andrade Haiduke
• Support type: Regular Research Grants