From correlation-consistent to polarization-consistent basis sets estimation of NMR spin–spin coupling constant in the B3LYP Kohn–Sham basis set limit

Based on B3LYP spin–spin coupling constants (SSCC) of several molecules calculated with cc-pVxZ, cc-pCVxZ, cc-pCVxZ-sd and cc-pCVxZ-sd+t basis sets, a reasonably fit, using the two-parameter formula, to the Kohn–Sham complete basis set limit (CBS) is shown. Improvement in the CBS values going from cc-pVxZ to the most elaborated cc-pCVxZ-sd+t basis set family is observed: standard deviation for all data drops from 33.7 to 23.1, and from 6.0 to 4.8 Hz after excluding problematic 1J(F,H) and 1J(F,C). Calculation of water’s 1J(OH) using B3LYP/cc-pCVxZ and B3LYP/pcJ-n significantly improved the FC term convergence.