2-methylnaphthalene C11H10
A_69789470db · SMILES Cc1ccc2ccccc2c1 · InChIKey QIMMUPPBPVKWKM-UHFFFAOYSA-N
Infrared spectrum at the cheap level (B3LYP/6-31G*, the pipeline's input)
How to read this
40 infrared-active bands (500–3500 cm⁻¹); the strongest at 3193 cm⁻¹ (3.1 µm), 43 km/mol.
cheap input (B3LYP): blue curve, sticks orange at the curve's peak scale. Lorentzian, FWHM 10 cm⁻¹; axis in km mol⁻¹ per cm⁻¹.
Band heights from the molecule's dipole derivatives and the same B3LYP Hessian as the listed positions (double harmonic).
Predicted spectrum (rung 3, the learned correction): computed by the pipeline, not drawn on this page; licensed for ring-ip, CH-stretch, CH-oop (decision 65).
How well is this shape known?
| measured on (ΔH network v1.3) | spectrum overlap cheap → corrected | height error cheap → corrected |
|---|---|---|
| 8 unseen simple aromatics (layer A), DFT stand-in for the higher level | 0.28 → 0.98 | 0.23 → 0.10 |
| 31 molecules of unseen scaffolds, DFT stand-in for the higher level | 0.37 → 0.97 | 0.51 → 0.24 |
| against coupled cluster | not measured for this version | |
Overlap: similarity of the two broadened spectra (1 = the same shape). Height error: relative error per band, weighted by height (0 = the same heights). "Corrected" is the learned correction on molecules it never saw; the pipeline serves it for the licensed families. Open: the dipole derivatives themselves are computed at the cheap level (on benzene they differ from coupled cluster by about 20 %).
Harmonic frequencies at the cheap level (deck v1: B3LYP and ωB97X, 6-31G*, at the B3LYP geometry)
57 vibrational modes; imaginary modes negative. Shift = ωB97X − B3LYP; height = B3LYP band height (km/mol).
The B3LYP bands are drawn in the spectrum above; the table adds their heights, the ωB97X positions and the shift.
| # | B3LYP (cm⁻¹) | height (km/mol) | ωB97X (cm⁻¹) | shift |
|---|---|---|---|---|
| 1 | 91.3 | 0.49 | 102.4 | +11.1 |
| 2 | 122.5 | 0.68 | 128.6 | +6.1 |
| 3 | 184.3 | 0.45 | 193.1 | +8.8 |
| 4 | 262.2 | 0.70 | 264.7 | +2.5 |
| 5 | 283.6 | 0.29 | 292.4 | +8.8 |
| 6 | 404.1 | 0.10 | 414.8 | +10.6 |
| 7 | 410.5 | 1.44 | 416.2 | +5.8 |
| 8 | 453.3 | 0.04 | 455.6 | +2.4 |
| 9 | 491.4 | 10.16 | 497.8 | +6.4 |
| 10 | 517.7 | 0.01 | 528.3 | +10.6 |
| 11 | 527.3 | 0.04 | 530.8 | +3.5 |
| 12 | 636.8 | 2.51 | 639.3 | +2.6 |
| 13 | 641.3 | 0.62 | 655.9 | +14.6 |
| 14 | 713.1 | 0.56 | 718.1 | +5.0 |
| 15 | 758.0 | 19.48 | 767.8 | +9.8 |
| 16 | 782.8 | 1.65 | 792.5 | +9.7 |
| 17 | 784.7 | 0.18 | 797.0 | +12.3 |
| 18 | 832.2 | 37.82 | 845.9 | +13.7 |
| 19 | 869.6 | 10.58 | 885.6 | +16.0 |
| 20 | 897.9 | 0.13 | 905.6 | +7.8 |
| 21 | 908.5 | 3.10 | 925.9 | +17.5 |
| 22 | 952.5 | 1.94 | 977.9 | +25.4 |
| 23 | 967.5 | 0.88 | 984.3 | +16.8 |
| 24 | 970.4 | 0.73 | 999.2 | +28.8 |
| 25 | 987.8 | 0.00 | 1018.3 | +30.5 |
| 26 | 1035.1 | 7.02 | 1036.8 | +1.7 |
| 27 | 1052.1 | 1.12 | 1059.7 | +7.5 |
| 28 | 1077.0 | 4.44 | 1083.9 | +6.9 |
| 29 | 1155.8 | 1.77 | 1157.5 | +1.7 |
| 30 | 1185.8 | 1.27 | 1165.6 | -20.2 |
| 31 | 1188.9 | 0.52 | 1188.7 | -0.2 |
| 32 | 1208.4 | 1.89 | 1211.7 | +3.3 |
| 33 | 1246.7 | 0.83 | 1242.0 | -4.6 |
| 34 | 1286.7 | 0.13 | 1290.5 | +3.8 |
| 35 | 1299.8 | 6.07 | 1305.4 | +5.6 |
| 36 | 1400.2 | 1.65 | 1397.9 | -2.3 |
| 37 | 1414.1 | 0.41 | 1408.7 | -5.4 |
| 38 | 1422.6 | 3.04 | 1427.4 | +4.8 |
| 39 | 1443.3 | 0.43 | 1453.0 | +9.7 |
| 40 | 1482.1 | 2.24 | 1495.4 | +13.2 |
| 41 | 1513.3 | 5.56 | 1516.3 | +3.0 |
| 42 | 1520.6 | 1.03 | 1530.5 | +9.9 |
| 43 | 1526.1 | 3.97 | 1538.2 | +12.2 |
| 44 | 1564.7 | 9.86 | 1591.0 | +26.3 |
| 45 | 1628.3 | 0.08 | 1660.0 | +31.7 |
| 46 | 1664.6 | 8.55 | 1691.9 | +27.3 |
| 47 | 1692.0 | 8.19 | 1738.1 | +46.2 |
| 48 | 3039.4 | 39.31 | 3074.9 | +35.5 |
| 49 | 3089.1 | 21.77 | 3139.8 | +50.7 |
| 50 | 3125.7 | 16.28 | 3172.7 | +47.0 |
| 51 | 3170.6 | 11.71 | 3215.0 | +44.5 |
| 52 | 3171.1 | 7.37 | 3215.5 | +44.5 |
| 53 | 3175.2 | 11.24 | 3218.5 | +43.3 |
| 54 | 3179.6 | 1.13 | 3223.1 | +43.6 |
| 55 | 3189.8 | 23.43 | 3233.4 | +43.6 |
| 56 | 3193.3 | 42.83 | 3236.5 | +43.2 |
| 57 | 3206.8 | 30.78 | 3249.4 | +42.6 |
Second route
Analytic Hessian (pyscf, grid 99/590) against the corpus finite differences: b3lyp max |Δω| 1 cm⁻¹; wb97x max |Δω| 10 cm⁻¹.
Provenance
- Releases: layerA2_2026-09-23, layerA2_2026-09-23b, layerA2_2026-09-24, layerA_2026-09-22
- Entered the corpus as: parent molecules chosen by hand (benzene, naphthalene, the PAH cores and their relatives) (layer A)
- Run: ubuntu-32gb-hel1-2, 2026-09-18 15:25:39 → 2026-09-18 16:03:05, 2246 s, peak 3.6 GB, deck 97ed2d67c66b
- Imaginary modes: B3LYP 0, ωB97X 0
- Cheap-level band heights: dipole derivatives dipole_b3lyp_cphf.npz, Hessian hessian_b3lyp.npz
- Source files: corpus factory · manifest