Reliability of Computing van der Waals Bond Lengths of Some Rare Gas Diatomics

• Published in: International journal of molecular sciences Vol. 23; no. 22; p. 13944
• Main Authors: Zhang, Yi-Liang, Li, Bin
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 11-11-2022; MDPI
• Subjects: ab initio computations; bond length; CCSD(T) method; Chemical bonds; Computational chemistry; Density functional theory; density-functional theory (DFT) methods; Digital music; Experiments; Gases; Hydrogen bonds; Methods; Molecular structure; Quantum physics; Quantum Theory; Reproducibility of Results; van der Waals molecules; density-functional theory (DFT) methods; van der Waals molecules; ab initio computations; bond length; computational chemistry; CCSD(T) method
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms232213944

When the bond lengths of 11 molecules containing van der Waals bonds are optimized by 572 methods and 20 basis sets, it is found that the best mean absolute deviations (MADs) of density-functional theory (DFT) methods are 0.005 Å (shown by APFD/6-311++G**), 0.007 Å (B2PLYPD3(Full)/aug-cc-pVQZ), and 0.010 Å (revDSDPBEP86/aug-cc-pVQZ), while the best MADs of ab initio methods are 0.008 Å (BD(T)/aug-cc-pVTZ) and 0.016 Å (MP4/aug-cc-pVQZ). Moreover, the best MADs calculated by 54 selected methods in combination with 60 other basis sets (such as 6-311++G, 6-31++G(3d'f,3p'd), and UGBS1V++) are not better. Therefore, these bond lengths can be calculated with extremely high accuracy by some special methods and basis sets, and CCSD(T) is also not as good as expected because its best MAD is only 0.023 Å (CCSD(T)/aug-cc-pVQZ).