A Computational Study on Closed‐Shell Molecular HexafluoridesMF6(M=S, Se, Te, Po, Xe, Rn, Cr, Mo, W, U) – Molecular Structure, Anharmonic Frequency Calculations, and Prediction of the NdF6Molecule

Abstract

AbstractQuantum chemical methods were used to study the molecular structure and anharmonic IR spectra of the experimentally known closed‐shell molecular hexafluoridesMF6(M=S, Se, Te, Xe, Mo, W, U). First, the molecular structures and harmonic frequencies were investigated using Density Functional Theory (DFT) with all‐electron basis sets and explicitly considering the influence of spin‐orbit coupling. Second, anharmonic frequencies and IR intensities were calculated with the CCSD(T) coupled cluster method and compared, where available, with IR spectra recorded by us. These comparisons showed satisfactory results. The anharmonic IR spectra provide means for identifying experimentally too little studied or unknownMF6molecules withM=Cr, Po, Rn. To the best of our knowledge, we predict the NdF6molecule for the first time and show it to be a true local minimum on the potential energy surface. We used intrinsic bond orbital (IBO) analyses to characterize the bonding situation in comparison with the UF6molecule.