Spectrum Atlas

carbazole+COOH C13H9NO2

A2_1e3ee2b3a8 · SMILES O=C(O)c1ccc2[nH]c3ccccc3c2c1 · InChIKey UZRJWXGXZKPSJO-UHFFFAOYSA-N

Cheap level done
finite-difference Hessian noisyfinite-difference Hessian noisy (analytic check differs > 15 cm⁻¹). The finite-difference Hessian and the analytic Hessian of the same geometry differ by more than 15 cm⁻¹ on at least one frequency; the numerical route is the noisy one.

Infrared spectrum at the cheap level (B3LYP/6-31G*, the pipeline's input)

500100015002000250030003500 3 µm4 µm5 µm6 µm8 µm10 µm15 µm 0.05.010152025 wavenumber (cm⁻¹) 500100015002000250030003500 3 µm4 µm5 µm6 µm8 µm10 µm15 µm 0.05.010152025 wavenumber (cm⁻¹) 100020003000 3 µm5 µm10 µm 0.05.010152025 wavenumber (cm⁻¹)
cheap input (B3LYP) bands
How to read this

42 infrared-active bands (500–3500 cm⁻¹); the strongest at 1202 cm⁻¹ (8.3 µm), 424 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 level0.28 → 0.980.23 → 0.10
31 molecules of unseen scaffolds, DFT stand-in for the higher level0.37 → 0.970.51 → 0.24
against coupled clusternot 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)

69 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
159.71.9388.3+28.6
278.90.36105.5+26.6
3125.02.00135.4+10.5
4128.00.73137.3+9.3
5193.10.01205.3+12.1
6248.20.28256.3+8.1
7298.33.96309.0+10.7
8320.21.81322.7+2.6
9328.215.13343.7+15.5
10380.274.30414.5+34.3
11435.43.89447.0+11.5
12455.90.01464.4+8.6
13468.11.94473.3+5.2
14478.65.13484.4+5.8
15551.011.41555.5+4.5
16554.859.51578.8+24.0
17580.10.03595.9+15.8
18597.039.61603.5+6.5
19634.537.77643.6+9.1
20639.53.09668.8+29.2
21660.248.51669.2+9.0
22737.810.93746.0+8.3
23740.662.91758.6+18.0
24759.99.78776.1+16.2
25772.551.85793.6+21.1
26790.39.39807.1+16.8
27814.51.70822.8+8.3
28831.58.93850.9+19.4
29862.70.03877.1+14.4
30868.23.55889.1+20.9
31908.71.31916.9+8.2
32929.61.26964.3+34.7
33942.73.44968.0+25.2
34956.01.41984.8+28.8
35971.00.011002.8+31.8
361034.44.351041.8+7.4
371050.28.531060.5+10.3
381111.452.831124.0+12.7
391144.318.041152.1+7.8
401168.059.901168.0-0.0
411187.623.151183.5-4.1
421202.0423.621232.2+30.2
431237.125.111243.9+6.8
441249.22.671260.9+11.7
451269.584.031277.1+7.6
461319.838.381319.3-0.4
471325.910.231333.0+7.0
481366.951.181353.8-13.1
491386.037.581363.8-22.3
501391.9175.981411.5+19.6
511447.934.831450.2+2.3
521493.135.971509.7+16.6
531505.514.401522.4+16.9
541528.41.091549.7+21.3
551542.322.241564.1+21.9
561628.10.911659.0+30.8
571637.99.471670.6+32.6
581662.3126.151696.7+34.4
591680.326.891726.5+46.2
601813.0309.681847.0+34.0
613184.81.343227.7+42.9
623191.42.263234.3+42.8
633195.813.023238.9+43.2
643201.028.233244.0+43.0
653213.426.893255.9+42.5
663222.21.733264.8+42.7
673235.52.453279.1+43.7
683660.360.473707.2+47.0
693701.480.453741.7+40.3

Second route

Analytic Hessian (pyscf, grid 99/590) against the corpus finite differences: b3lyp max |Δω| 2 cm⁻¹; wb97x max |Δω| 16 cm⁻¹.

Provenance

  • Releases: layerA2_2026-09-23, layerA2_2026-09-23b, layerA2_2026-09-24
  • Entered the corpus as: substituted three- and four-ring cores, enumerated from the parents (layer A′) (layer A2)
  • Run: ubuntu-32gb-hel1-11, 2026-09-21 12:38:03 → 2026-09-21 14:07:14, 5350 s, peak 5.88 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