I will discuss some of the aspects, which are important for obtaining high accuracy in the calculation of nuclear magnetic resonance (NMR) indirect nuclear spin-spin coupling constants (SSCC). To illustrate the issue, I will firstly present results of our recent study of the vicinal fluorine-fluorine couplings in difluoroethyne [1]. Secondly, I will discuss the importance of triples corrections in the calculation of SSCCs with unpublished CCSD, CC3 and CCSDT results for some multiply bonded or organofluorine compounds [2]. Thirdly, I want to illustrate the need for specialized one-electron basis sets such as the aug-cc-pVTZ-J basis sets [3] or the ccJ-pVXZ [4] series of basis sets in CCSD calculations of SSCCs [5]. Finally, I intend to discuss the calculation of vibrational corrections to SSCCs in some organic molecules [6,7].



[1] Faber, R.; Sauer, S.P.A. On the Discrepancy between Theory and Experiment for the F-F Spin-Spin Coupling Constant of Difluoroethyne, Phys. Chem. Chem. Phys., 2012, 14, 16440-16447.
[2] Faber, R.; Sauer, S.P.A.; Gauss, J. to be published.
[3] Provasi, P. F.; Aucar, G. A.; Sauer, S. P. A. The effect of lone-pairs and electronegativity on the indirect nuclear spin-spin coupling constants in CH2X (X = CH2, NH, O, S). Ab initio calculations using optimized contracted basis sets, J. Chem. Phys. 2001, 115, 1324-1334 (2001); Barone, V.; Provasi, P. F.; Peralta, J. E.; Snyder, J. P.; Sauer, S. P. A.; Contreras, R. H. Substituent Effects on Scalar 2J(19F, 19F) and 3J(19F,19F) NMR Couplings: A Comparison of SOPPA and DFT Methods, J. Phys. Chem. A 2003, 107, 4748-4754; Provasi, P. F.; Sauer, S. P. A. Optimized Basis Sets for the Calculation of Indirect Nuclear Spin-Spin Coupling Constants Involving the Atoms B, Al, Si, P and Cl, J. Chem. Phys. 2010, 133, 054308.
[4] Benedikt, U.; Auer, A.A.; Jensen, F. Optimization of augmentation functions for correlated calculations of spin-spin coupling constants and related properties, J. Chem. Phys. 2008, 129, 064111.
[5] Faber, R.; Sauer, S.P.A. to be published.
[6] Faber, R.; Sauer, S.P.A. SOPPA and CCSD vibrational corrections to NMR indirect spin-spin coupling constants of small hydrocarbons, AIP Conf. Proc. 2015, 1702, 090035.
[7] Faber, R.; Kaminsky, J.; Sauer, S. P. A. Rovibrational and temperature effects in theoretical studies of NMR parameters, in Jackowski, K.; Jaszuński, M. eds.,Gas Phase NMR, Royal Society of Chemistry 2016, Chapter 7, pp. 219-268.