TABLE 1.
Relative Energies within a Family of Structures for the Conformers of (Arg·Arg + H)+ Calculated Using Mechanics (MMFF) and DFT (EDF1 6-31+G*//EDF1 6-31G*)a
| conformer | drms,min (Å) | rel energy (MMFF) (kcal/mol) | EDF1//EDF1 energy (hartrees) | rel energy (EDF1) (kcal/mol) |
|---|---|---|---|---|
| Salt Bridge (I) | ||||
| 1 | 0.8 | 0.0 | −1213.723 978 | 0.0 |
| 2 | 0.5 | 2.7 | −1213.717 993 | 3.8 |
| 3 | 0.5 | 2.8 | −1213.714 672 | 5.8 |
| 4 | 0.8 | 3.1 | −1213.722 417 | 1.0 |
| 5 | 0.8 | 3.8 | −1213.722 482 | 0.9 |
| 6 | 1.5 | 4.8 | −1213.713 150 | 7.0 |
| 7 | 0.8 | 5.1 | −1213.718 635 | 3.4 |
| 8 | 1.6 | 9.3 | −1213.711 385 | 7.9 |
| Ion–Molecule (II) | ||||
| 1 | 0.6 | 0.0 | −1213.711 205 | 0.0 (8.0) |
| 2 | 0.6 | 2.9 | −1213.712 192 | −0.6 (7.4) |
| 3 | 1.0 | 3.1 | −1213.701 312 | 6.2 (14.2) |
| 4 | 1.0 | 4.5 | −1213.706 606 | 2.9 (10.9) |
| 5 | 1.8 | 5.0 | −1213.702 797 | 5.3 (13.3) |
| 6 | 1.8 | 8.8 | −1213.692 727 | 12.2 (18.2) |
| 7 | 1.9 | 9.6 | −1213.692 044 | 12.6 (18.6) |
| 8 | 1.8 | 17.0 | −1213.683 011 | 17.7 (25.7) |
| Ion–Molecule (III) | ||||
| 1 | 1.7 | 0.0 | −1213.712 470 | 0.0 (7.2) |
| 2 | 0.8 | 3.3 | −1213.705 170 | 4.6 (11.8) |
| 3 | 0.8 | 5.4 | −1213.697 273 | 9.5 (16.7) |
| 4 | 1.7 | 5.7 | −1213.705 553 | 4.3 (11.5) |
a
The values in parentheses are the DFT energies of the conformer relative to the most stable conformer (I1).