Table 2 Comparison of the calculated and experimental vibrational spectra and proposal assignments of 2TSET.
Mode type & assignment | Observed FT-IR (cm-1) | Observed FT-Raman (cm-1) | Calculated (B3LYP/6-311 + G(d, p)) | Calculated (B3LYP/6-311 + G(d,2p)) | Major PED (%) |
|---|---|---|---|---|---|
νCH aromatic | 3106, 3091, 3078 | 3107 | 3112, 3080 | 3008, 3077 | 98 |
ν_as CH₃ | 3029–2852 | 2962, 2852 | 2966–2812 | 2960–2810 | 96–97 |
ν_s CH₃ | 2835, 2806, 2789 | 2791 | 2794–2790 | 2830–2790 | 96 |
νC = C aromatic | 2147, 1513 | 2148, 1514 | 2150, 1520 | 2145, 1515 | 72–88 |
γCH₃ | 1419–1370 | — | 1425–1368 | 1420–1368 | 75–78 |
βCH₃ | 1350, 1330, 1299 | 1351 | 1372–1308 | 1352–1300 | 75–76 |
νSi–CH₃ | 1280, 1250, 1236 | 1251, 1236 | 1253–1238 | 1250–1235 | 75–78 |
δCH/νC–C mixed | 1164, 1139 | 1164 | 1170–1145 | 1165–1140 | 75 |
δsbCH₃ | 1077, 1042 | 1078, 1044 | 1081, 1048 | 1080, 1045 | 76 |
δCH/νC–C mixed | 942, 853 | 854 | 940, 857 | 854 | 68–74 |
νC–S | 791, 759 | 756 | 798, 768 | 790, 760 | 72 |
γop rCH₃ | 732–685 | 733, 699 | 738–680 | 735–675 | 70–72 |
γC–Si/δC–Si | 678–572 | 640, 571 | 680–578 | 675–572 | 63–70 |
Low-frequency modes | 532–14 | 512, 416 | 527–12 | 512–12 | 48–54 |
