title: Estimation of isotropic nuclear magnetic shieldings in the CCSD(T) and MP2 complete basis set limit using affordable correlation calculations.
abstract: A linear correlation between isotropic nuclear magnetic shielding constants for seven model molecules (CH2 O, H2 O, HF, F2 , HCN, SiH4 and H2 S) calculated with 37 methods (34 density functionals, RHF, MP2 and CCSD(T)), with affordable pcS-2 basis set and corresponding complete basis set results, estimated from calculations with the family of polarization-consistent pcS-n basis sets is reported. This dependence was also supported by inspection of profiles of deviation between CBS estimated nuclear shieldings and shieldings obtained with the significantly smaller basis sets pcS-2 and aug-cc-pVTZ-J for the selected set of 37 calculation methods. It was possible to formulate a practical approach of estimating the values of isotropic nuclear magnetic shielding constants at the CCSD(T)/CBS and MP2/CBS levels from affordable CCSD(T)/pcS-2, MP2/pcS-2 and DFT/CBS calculations with pcS-n basis sets. The proposed method leads to a fairly accurate estimation of nuclear magnetic shieldings and considerable saving of computational efforts.
authors.affiliation: University of Opole, Faculty of Chemistry, 45-052 Opole, Poland. teobaldk@yahoo.com
authors.forename: Teobald
authors.initials: T
authors.lastname: Kupka
authors.forename: Michał
authors.initials: M
authors.lastname: Stachów
authors.forename: Jakub
authors.initials: J
authors.lastname: Kaminsky
authors.forename: Stephan P A
authors.initials: SP
authors.lastname: Sauer
mesh_terms: D005459:Fluorides / Q000737:chemistry; D005557:Formaldehyde / Q000737:chemistry; D006858:Hydrofluoric Acid / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry; D006856:Hydrogen Cyanide / Q000737:chemistry; D006862:Hydrogen Sulfide / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D011789:Quantum Theory; D012825:Silicon / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water; D005557:Formaldehyde; D006856:Hydrogen Cyanide; D006859:Hydrogen; D005459:Fluorides; D006858:Hydrofluoric Acid; D006862:Hydrogen Sulfide; D012825:Silicon
keywords: CBS; CCSD(T); DFT; aug-cc-pVTZ-J; isotropic nuclear magnetic shielding; pcS-2