Table 1. Summary of the Robustness Analysis Performed for the Modes in the Amide II Spectral Region: the Number of Normal Modes (No. NMs) and the Number of VCD Sign Changes (No. Sign Changes) Observed When Comparing Calculations Performed with Six Different Computational Parameters (BP86/DZP, BP86/TZP, BP86/TZ2P, OLYP/DZP, OLYP/TZP, and OLYP/TZ2P).
| A-type modes |
B-type modes |
C-type modes |
all modes |
|||||
|---|---|---|---|---|---|---|---|---|
| conformer | no. NMs | no. sign changes | no. NMs | no. sign changes | no. NMs | no. sign changes | no. NMs | no. sign changes |
| α2* | 2 | 1 | 0 | 0 | 6 | 1 | 8 | 2 |
| α3* | 2 | 0 | 0 | 0 | 6 | 5 | 8 | 5 |
| α4* | 2 | 1 | 1 | 0 | 5 | 1 | 8 | 2 |
| β4* | 1 | 1 | 5 | 1 | 2 | 1 | 8 | 3 |
| total H bonding | 7 | 3 | 6 | 1 | 19 | 8 | 32 | 12 |
| α1 | 2 | 0 | 4 | 2 | 2 | 0 | 8 | 2 |
| β1 | 2 | 1 | 3 | 2 | 3 | 1 | 8 | 4 |
| β2 | 2 | 0 | 4 | 1 | 2 | 2 | 8 | 3 |
| β3 | 2 | 0 | 2 | 0 | 4 | 3 | 8 | 3 |
| total rest | 8 | 1 | 13 | 5 | 11 | 6 | 32 | 12 |
| total all modes | 15 | 4 | 19 | 6 | 30 | 14 | 64 | 24 |
| total all α modes | 8 | 2 | 5 | 2 | 19 | 7 | 32 | 11 |
| total all β modes | 7 | 2 | 14 | 4 | 11 | 7 | 32 | 13 |