Table 1.
Spectral peak assignments
| Far field | Gold SERS | Silver SERS | Silver TERS | Proposed assignment |
|||
|---|---|---|---|---|---|---|---|
| Phenylalanine ring (Wilson vibration number, group, and range) (22,29,34–37,39) | Tyrosine ring (Wilson vibration number, group, and range) (22,29,34–37,39) | Amide (27,28,40,42,43) | Other (22,27,28,34–36) | ||||
| 645 | 665 | — | 6b, B3g (630 ± 20) | COO− wag. | |||
| 685 | — | 4, B1 (690 ± 10) | 4, B2g (700 ± 35) | ||||
| 765 | — | ||||||
| 795 | — | A1 (725 ± 75) | Ag (820 ± 50) | ||||
| 835 | — | 10a, A2 (835 ± 25) | 10a, B1g (820 ± 30) | CH | |||
| 945 | 940 | — | 17a, A1 (960 ± 20) | 17a, Au (960 ± 30) | C-COO− | ||
| 1002 | 995 | — | 12, A1 (1000 ± 10) | ||||
| 1025 | 1025 | — | 18a, A1 (1024 ± 6) | 18a, B1u (1012 ± 9) | |||
| 1065 | — | 18b, B2 (1074 ± 8) | |||||
| 1165 | 1155 | 15, B2 (1156 ± 5) | 9a, Ag (1166 ± 24) | ||||
| 1195 | 1175 | 9a, A1 (1175 ± 5) | |||||
| 1215 | A1 (1205) | Ag (1210 ± 15) | |||||
| 1245 | 1235 | B1u (1250 ± 15) | Amide III | ||||
| 12461289 | Amide III | CH | |||||
| 1265 | 1285 | 1275 | 3, B2 (1275 ± 20) | 3, B3g (1286 ± 26) | Amide III | CH | |
| 1355 | 1335 | 14, B2u (1310 ± 70) | CH | ||||
| 1405 | 1410 | 1415 | 19b, B2u (1420 ± 50) | COO− sym. (1390 ± 50) | |||
| 14451449 | 1445 | 1445 | 1460 | 19b, B2 (1455 ± 16) | CH | ||
| 1485 | 1485 | 1515 | 19a, A1 (1492 ± 22) | 19a, B1u (1495 ± 35) | |||
| 1530 | |||||||
| 1565 | 1565 | Amide II | |||||
| 1585 | 1585 | 1585 | 8b, B2 (1579 ± 18) | 8b, B3g (1578 ± 26) | COO− asym. | ||
| 1605 | 1605 | 8a, A1 (1594 ± 20) | 8a, Ag (1600 ± 29) | COO− asym. | |||
| 1627 | 1632∗ | Amide I (310-helix) | COO- asym.† (1620 ± 70) | ||||
| 1649 | 1656 | Amide I (α-helix) | COO− asym. | ||||
| 1675 | 1675 | Amide I (β-sheet) | COO− asym. | ||||