stilbene_E C14H12

A_7a57a52879 · SMILES C(=C\c1ccccc1)/c1ccccc1 · InChIKey PJANXHGTPQOBST-VAWYXSNFSA-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

22 infrared-active bands (500–3500 cm⁻¹); the strongest at 3203 cm⁻¹ (3.1 µm), 74 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 — 2026-09-18, ubuntu-32gb-hel1-2
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	-4.7	0.00	57.6	+62.3
2	59.9	0.36	74.0	+14.1
3	68.1	0.00	94.2	+26.1
4	81.7	0.24	94.7	+13.0
5	205.8	0.00	211.5	+5.7
6	222.3	0.00	222.8	+0.5
7	287.7	0.03	293.1	+5.5
8	289.0	0.00	296.5	+7.5
9	412.6	0.03	423.5	+10.9
10	413.6	0.00	424.7	+11.0
11	474.5	2.01	473.2	-1.3
12	477.4	0.02	485.1	+7.6
13	543.6	10.22	551.8	+8.2
14	551.5	20.47	556.0	+4.5
15	633.0	0.00	636.7	+3.7
16	636.6	0.01	640.3	+3.7
17	655.1	0.00	660.6	+5.5
18	700.5	0.00	713.6	+13.2
19	705.4	50.40	716.1	+10.7
20	752.8	0.00	764.0	+11.2
21	782.7	56.55	796.9	+14.2
22	837.1	0.26	846.4	+9.3
23	847.3	0.00	866.1	+18.9
24	849.0	0.11	868.9	+19.9
25	879.0	0.00	897.0	+18.0
26	885.9	0.00	899.8	+13.9
27	918.2	2.23	941.6	+23.4
28	928.9	0.00	953.7	+24.8
29	961.2	0.17	993.9	+32.7
30	962.4	0.00	994.8	+32.5
31	986.6	4.29	1014.2	+27.6
32	991.5	0.00	1020.9	+29.4
33	1012.8	26.96	1022.2	+9.4
34	1015.0	0.01	1022.6	+7.7
35	1015.3	0.08	1030.2	+14.9
36	1058.0	0.00	1068.7	+10.7
37	1060.5	3.33	1071.3	+10.8
38	1113.1	6.94	1122.3	+9.2
39	1115.9	0.01	1125.3	+9.3
40	1192.8	0.25	1185.9	-6.8
41	1193.0	0.01	1186.1	-6.9
42	1216.8	0.24	1219.6	+2.8
43	1219.0	0.00	1223.5	+4.5
44	1222.8	0.00	1239.6	+16.8
45	1265.4	1.24	1260.5	-4.9
46	1306.9	1.94	1312.8	+5.9
47	1346.2	0.00	1320.7	-25.5
48	1367.8	0.00	1360.3	-7.4
49	1372.9	1.28	1361.7	-11.2
50	1381.7	0.00	1386.0	+4.3
51	1387.1	4.61	1387.1	-0.0
52	1493.4	0.00	1506.3	+12.9
53	1502.4	11.10	1513.9	+11.4
54	1542.7	0.01	1556.0	+13.4
55	1551.2	28.40	1567.0	+15.8
56	1630.5	0.00	1662.5	+32.1
57	1636.0	2.79	1667.2	+31.3
58	1655.5	0.00	1699.0	+43.4
59	1663.7	18.54	1703.5	+39.8
60	1705.7	0.00	1745.3	+39.6
61	3155.9	0.00	3205.4	+49.5
62	3163.6	25.45	3208.4	+44.8
63	3176.3	18.02	3219.7	+43.4
64	3176.3	9.17	3219.7	+43.4
65	3183.3	0.00	3226.6	+43.3
66	3183.9	0.35	3227.0	+43.2
67	3193.5	33.21	3236.9	+43.4
68	3193.8	0.16	3237.0	+43.2
69	3203.2	4.75	3247.2	+43.9
70	3203.6	69.32	3247.3	+43.7
71	3211.0	54.16	3254.2	+43.2
72	3211.6	0.42	3254.8	+43.2

Second route

Analytic Hessian (pyscf, grid 99/590) against the corpus finite differences: b3lyp max |Δω| 8 cm⁻¹; wb97x max |Δω| 20 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 19:04:33 → 2026-09-18 20:12:52, 4098 s, peak 4.99 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