Ab Initio NMR Chemical Shift Calculations Using Fragment Molecular Orbitals and Locally Dense Basis Sets

We revisit the NMR shielding constants of a model 10-residue peptide system by investigating the use of Jensen's NMR specialized basis sets and locally dense basis sets within the fragmentation molecular orbital scheme. It is found that this procedure can reproduce the shielding constants of a full calculation at only a fraction of the cost. Strategies for choosing fragments and complications that need to be considered within the method are discussed extensively.