2018/01/04 by Régis T. Santiago, Roberto L. A. Haiduke · 2 citations
Physics and Astronomy · Chemistry · Mathematics · #Advanced Chemical Physics Studies #Atomic and Molecular Physics #Inorganic Fluorides and Related Compounds #Relativistic quantum chemistry #Chemistry #Scalar (mathematics) #Planar #Basis set #Ground state #Coupled cluster #Molecule #Electronic structure #Wave function #Atomic physics #Physics #Computational chemistry #Geometry #Density functional theory #Mathematics
paper · doi:10.1002/qua.25585
openalex publication_date 2018/01/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
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, XH 3 (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 BiH 3 , 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.