Table 1.
Assignment of vibrational modes in SERS Spectra of Rhodamine 6G dye (R6G) and picric acid (PA).
| PA Raman Shift (cm−1) | Assignment [3] | R6G Raman Shift (cm−1) | Assignment [35,36] |
|---|---|---|---|
| 825 | C–H bending | 612 | C−C ring in-plane bending in xanthene/phenyl rings |
| 938 | ring breathing | 772 | C−H out-of-plane bending |
| 1088 | phenolic C–O stretching | 797 | hybrid mode (xanthene/phenyl rings and NHC2H5 group) |
| 1330 | C–C stretching | 1127 | C−H in-plane bending in xanthene/phenyl rings |
| 1335 | NO2 symmetric stretching | 1187 | C−H in-plane bending in xanthene ring |
| 1564 | C–NO2 asymmetric stretching | 1204 | hybrid mode (xanthene/phenyl rings) |
| 1275 | C−O−C stretching in COOC2H5 group on phenyl ring | ||
| 1312 | hybrid mode (xanthene/phenyl rings and NHC2H5 group) | ||
| 1363 | C−C stretching in xanthene ring | ||
| 1449 | C−N stretching in NHC2H5 | ||
| 1509 | C−C stretching in xanthene ring | ||
| 1575 | C−C stretching in phenyl ring | ||
| 1595 | hybrid mode (phenyl ring with COOC2H5 | ||
| 1651 | C−C stretching in xanthene ring |