Systematic Study of Locally Dense Basis Sets for NMR Shielding Constants

David M Reid; Rika Kobayashi; Michael A Collins

doi:10.1021/ct4007579

Systematic Study of Locally Dense Basis Sets for NMR Shielding Constants

J Chem Theory Comput. 2014 Jan 14;10(1):146-52. doi: 10.1021/ct4007579.

Authors

David M Reid¹, Rika Kobayashi², Michael A Collins¹

Affiliations

¹ Research School of Chemistry, The Australian National University , Acton ACT 0200, Australia.
² Australian National University Supercomputer Facility, The Australian National University , Acton ACT 0200, Australia.

PMID: 26579898
DOI: 10.1021/ct4007579

Abstract

This paper presents a systematic study of partitioning schemes for locally dense basis sets in the context of NMR shielding calculations. The partitionings explored were based exclusively on connectivity and utilized the basis sets from the pcS-n series. Deviations from pcS-4 shieldings were calculated for a set of 28 organic molecules at the HF, B3LYP, and KT3 levels of theory, with the primary goal being the determination of an efficient scheme that achieves maximal deviations of 0.1 ppm for (1)H and 1 ppm for (13)C. Both atom based and group based divisions of basis sets were examined, with the latter providing the most promising results. It is demonstrated that for the systems studied, at least pcS-1 is required for all parts of the molecule. This, coupled with pcS-3 on the group of interest and pcS-2 on the adjacent groups, is sufficient to achieve the desired level of accuracy at a minimal computational expense. In addition, the suitability of the pcS-n basis sets for post-SCF methods was confirmed through a comparison with other standard basis sets at the MP2 level.