biphenylene C12H8
A_72b86c2331 · SMILES c1ccc2c(c1)-c1ccccc1-2 · InChIKey IFVTZJHWGZSXFD-UHFFFAOYSA-N
Infrared spectrum at the cheap level (B3LYP/6-31G*, the pipeline's input)
How to read this
18 infrared-active bands (500–3500 cm⁻¹); the strongest at 751 cm⁻¹ (13.3 µm), 103 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)
54 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 | 107.0 | 1.87 | 121.2 | +14.2 |
| 2 | 150.5 | 0.00 | 162.6 | +12.1 |
| 3 | 214.7 | 0.67 | 222.9 | +8.2 |
| 4 | 324.5 | 0.00 | 331.8 | +7.3 |
| 5 | 382.3 | 1.43 | 393.7 | +11.4 |
| 6 | 401.6 | 0.00 | 406.0 | +4.4 |
| 7 | 449.9 | 0.00 | 446.1 | -3.8 |
| 8 | 466.8 | 0.00 | 479.0 | +12.2 |
| 9 | 567.9 | 0.00 | 568.5 | +0.6 |
| 10 | 586.5 | 0.00 | 601.0 | +14.6 |
| 11 | 614.6 | 0.00 | 619.6 | +5.1 |
| 12 | 627.8 | 4.24 | 632.1 | +4.3 |
| 13 | 719.3 | 0.00 | 739.1 | +19.8 |
| 14 | 736.7 | 0.34 | 745.6 | +8.9 |
| 15 | 751.2 | 103.19 | 763.1 | +11.9 |
| 16 | 762.8 | 0.00 | 777.1 | +14.3 |
| 17 | 783.9 | 0.00 | 791.7 | +7.8 |
| 18 | 824.7 | 0.00 | 835.5 | +10.8 |
| 19 | 884.7 | 0.00 | 907.5 | +22.9 |
| 20 | 902.0 | 0.00 | 924.7 | +22.7 |
| 21 | 918.7 | 6.02 | 951.2 | +32.6 |
| 22 | 923.5 | 0.00 | 957.2 | +33.6 |
| 23 | 970.5 | 0.00 | 1000.1 | +29.6 |
| 24 | 970.7 | 0.00 | 1003.3 | +32.6 |
| 25 | 999.2 | 17.81 | 1003.6 | +4.4 |
| 26 | 1001.4 | 0.00 | 1008.4 | +7.0 |
| 27 | 1022.4 | 0.00 | 1028.2 | +5.8 |
| 28 | 1056.7 | 0.00 | 1065.4 | +8.8 |
| 29 | 1076.2 | 1.21 | 1086.4 | +10.2 |
| 30 | 1119.6 | 0.00 | 1127.0 | +7.3 |
| 31 | 1142.3 | 0.00 | 1152.0 | +9.6 |
| 32 | 1155.5 | 10.52 | 1164.8 | +9.3 |
| 33 | 1191.3 | 9.97 | 1175.7 | -15.6 |
| 34 | 1200.6 | 0.00 | 1193.6 | -7.1 |
| 35 | 1305.3 | 2.02 | 1278.4 | -26.9 |
| 36 | 1317.2 | 31.21 | 1314.8 | -2.4 |
| 37 | 1321.5 | 0.00 | 1323.8 | +2.3 |
| 38 | 1450.0 | 0.00 | 1455.8 | +5.8 |
| 39 | 1477.5 | 31.99 | 1490.6 | +13.0 |
| 40 | 1492.7 | 5.17 | 1506.9 | +14.2 |
| 41 | 1495.5 | 0.00 | 1507.9 | +12.4 |
| 42 | 1520.7 | 0.00 | 1537.6 | +16.9 |
| 43 | 1642.6 | 1.69 | 1682.5 | +39.9 |
| 44 | 1649.0 | 0.52 | 1690.3 | +41.3 |
| 45 | 1657.1 | 0.00 | 1698.5 | +41.4 |
| 46 | 1721.5 | 0.00 | 1748.2 | +26.6 |
| 47 | 3182.7 | 0.00 | 3225.9 | +43.2 |
| 48 | 3183.0 | 0.53 | 3226.2 | +43.2 |
| 49 | 3195.0 | 20.41 | 3238.1 | +43.1 |
| 50 | 3195.8 | 0.02 | 3238.8 | +43.1 |
| 51 | 3204.5 | 0.01 | 3247.6 | +43.1 |
| 52 | 3205.5 | 60.82 | 3248.4 | +42.9 |
| 53 | 3210.5 | 51.89 | 3253.3 | +42.8 |
| 54 | 3211.8 | 1.38 | 3254.6 | +42.7 |
Second route
Analytic Hessian (pyscf, grid 99/590) against the corpus finite differences: b3lyp max |Δω| 1 cm⁻¹; wb97x max |Δω| 4 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 16:36:10 → 2026-09-18 17:11:07, 2097 s, peak 3.78 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