DFT methods were employed to compute the C-13 NMR chemical shift tensor (CST) parameters. for crystals of YAF peptides (Tyr-Ala-Phe) with different stereochemistry for the Ala residue. Tyr-D-Ala-Phe 1 crystallizes in the C2 space group while Tyr- L-Ala-Phe crystallizes in either the P2(1)2(1)2 space group (2a) or the P6(5) space group (2b). PISEMA MAS measurements for samples with a natural abundance of H-1 and C-13 nuclei and H-2 QUADECHO experiments for samples with deuterium labeled aromatic rings were used to analyze the geometry and time scale of the molecular motion. At ambient temperature, the tyrosine ring of sample 1 is rigid and the phenylalanine ring undergoes a pi-jump, both rings in sample 2a are static, and both rings in sample 2b undergo a fast regime exchange. The theoretical values of the CST were obtained for isolated molecules (IM) and clusters employing the ONIOM approach. The experimental C-13 delta(ii) parameters for all of the samples were measured via a 2D PASS sequence. Significant scatter of the computed versus the experimental C-13 CST parameters was observed for 1 and 2b, while the observed correlation was very good for 2a. In this report, we show that the quality of the C-13 sigma(ii)/C-13 delta(ii) correlations, when properly interpreted, can be a source of important information about local molecular motions.