fluorene+CH3 C14H12

A2_27edf7297c · SMILES Cc1ccc2c(c1)Cc1ccccc1-2 · InChIKey RKJHJMAZNPASHY-UHFFFAOYSA-N

Cheap level done

finite-difference Hessian noisy

finite-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)

cheap input (B3LYP) bands

How to read this

53 infrared-active bands (500–3500 cm⁻¹); the strongest at 3194 cm⁻¹ (3.1 µm), 52 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 %).

Structure

2D depiction from the SMILES.

Status ladder

Listed
Cheap level done — 2026-09-22, ubuntu-32gb-hel1-9
Correction predicted — not yet: the learned layer is training
Spectrum predicted — not yet: the learned layer is training
Anchored
Validated

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Not available on this site yet: the pipeline (a molecule in, its spectrum and certificate out) runs on the project's own computer, with three of the four mode families licensed at the DFT stand-in level. Sign-in will be needed only to request runs; reading stays open.

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Harmonic frequencies at the cheap level (deck v1: B3LYP and ωB97X, 6-31G*, at the B3LYP geometry)

72 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	29.7	0.28	76.2	+46.5
2	74.2	0.38	111.5	+37.3
3	135.8	0.00	150.4	+14.6
4	184.4	0.27	190.6	+6.1
5	198.5	0.32	209.4	+10.9
6	245.1	4.90	264.7	+19.6
7	318.8	0.08	322.6	+3.8
8	332.5	0.75	343.8	+11.3
9	398.8	0.13	402.9	+4.1
10	429.7	4.91	440.9	+11.2
11	443.0	0.20	451.9	+8.9
12	503.6	0.12	514.5	+10.9
13	510.3	0.42	516.8	+6.4
14	553.5	0.92	558.0	+4.5
15	583.8	1.80	589.2	+5.4
16	587.6	1.23	597.6	+10.0
17	657.9	1.46	662.5	+4.6
18	713.0	0.00	727.9	+14.9
19	722.7	1.56	730.7	+8.0
20	749.2	26.41	762.8	+13.6
21	773.7	0.39	780.9	+7.2
22	784.4	30.82	798.0	+13.6
23	836.8	0.43	844.9	+8.1
24	837.6	12.09	853.4	+15.8
25	878.0	0.06	898.7	+20.7
26	894.0	1.04	910.5	+16.4
27	932.5	0.23	943.6	+11.1
28	933.0	0.21	962.6	+29.6
29	948.9	0.16	977.9	+29.0
30	976.8	1.63	995.6	+18.8
31	980.1	1.70	1011.1	+31.0
32	1023.9	1.55	1031.3	+7.4
33	1029.2	0.52	1034.2	+5.0
34	1057.0	2.60	1067.8	+10.8
35	1073.8	14.17	1082.1	+8.3
36	1126.7	0.82	1135.5	+8.8
37	1153.8	1.85	1162.8	+8.9
38	1167.3	0.02	1170.9	+3.6
39	1169.3	1.51	1186.0	+16.6
40	1189.5	0.28	1189.4	-0.0
41	1207.2	3.25	1218.4	+11.3
42	1233.3	1.13	1242.7	+9.4
43	1246.6	1.93	1250.5	+3.8
44	1278.8	2.23	1289.1	+10.4
45	1328.5	0.47	1320.0	-8.5
46	1339.6	0.01	1326.8	-12.8
47	1355.4	13.97	1356.2	+0.9
48	1388.5	0.54	1376.9	-11.7
49	1442.5	1.62	1453.0	+10.6
50	1469.4	3.62	1484.0	+14.6
51	1480.6	6.98	1496.2	+15.6
52	1504.0	15.53	1518.6	+14.6
53	1513.0	16.92	1523.8	+10.8
54	1517.9	5.80	1527.6	+9.7
55	1528.2	8.16	1541.2	+13.0
56	1536.2	6.12	1560.4	+24.2
57	1631.7	1.28	1663.7	+32.0
58	1640.3	0.38	1673.8	+33.6
59	1665.9	4.62	1706.7	+40.7
60	1672.5	2.25	1716.7	+44.2
61	3034.1	17.14	3074.0	+39.9
62	3037.1	43.95	3077.3	+40.3
63	3061.8	12.89	3116.8	+55.0
64	3094.0	23.99	3143.3	+49.3
65	3122.2	16.44	3170.1	+47.9
66	3169.5	24.57	3213.2	+43.7
67	3173.6	18.55	3217.5	+43.9
68	3175.9	4.83	3219.3	+43.4
69	3182.0	3.82	3225.5	+43.5
70	3192.2	0.58	3236.0	+43.8
71	3194.4	51.80	3236.9	+42.6
72	3205.9	36.79	3248.8	+42.9

Second route

Analytic Hessian (pyscf, grid 99/590) against the corpus finite differences: b3lyp max |Δω| 2 cm⁻¹; wb97x max |Δω| 25 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-hel1-9, 2026-09-22 01:57:17 → 2026-09-22 03:12:42, 4524 s, peak 5.32 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