An Efficient Method for Contraction of Property-Oriented Basis Sets: A Considerable Reduction of the pecJ-1 and pecJ-2 Basis Sets for the Calculations of Spin–Spin Coupling Constants Involving H, C, N and F Nuclei

In this paper, it is suggested that the property–energy consistent (PEC) method represents an efficient and reliable method for generating accurate contraction coefficients for the property-oriented basis sets. Due to its peculiarities, the PEC method allows the implementation of rather succinct contraction schemes, without a noticeable loss of accuracy, giving in result very compact property-oriented basis sets that are capable of providing the same or even better accuracy than that reached with considerably larger basis sets of the same kind. This idea has been demonstrated on the example of the recontraction of previously introduced spin–spin coupling constant (SSCC)-oriented pecJ-n (n = 1, 2) basis sets for H, C, N, and F atoms, whose exponents were optimized by the PEC algorithm, but the contraction coefficients were defined using the usual self-consistent field calculations of the molecular energies of the simplest hydrides. In this work, the original pecJ-n basis sets were recontacted by means of the PEC method, resulting in compact segmented–contracted basis sets being smaller in size than their previous analogies by four and seven functions for hydrogen and the 2nd-period atoms, respectively. High-quality SOPPA(CCSD) calculations of 436 SSCCs of various types involving H, C, N, and F nuclei showed the supremacy of the newly contracted pecJ-n (n = 1, 2) basis sets over their original versions and most of the other well-known SSCC-oriented basis sets.