naphthalene+Cl+OCH3 C11H9ClO

B_12bcbb49e2 · SMILES COc1cc(Cl)c2ccccc2c1 · InChIKey LJHLBVBZMDGPMO-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

42 infrared-active bands (500–3500 cm⁻¹); the strongest at 1313 cm⁻¹ (7.6 µm), 241 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 — 2026-09-27, ubuntu-32gb-hel1-16
Correction predicted — not yet: the learned layer is training
Spectrum predicted — not yet: the learned layer is training
Anchored
Validated

Request a run

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.

Notify me when this molecule climbs the ladder: open a GitHub issue — you are subscribed to it and we close it with a link when the page changes. No e-mail address is stored by this site.

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

60 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	64.5	3.90	97.1	+32.6
2	115.3	0.58	131.7	+16.4
3	151.2	0.25	169.8	+18.7
4	187.0	1.66	196.1	+9.1
5	196.5	0.35	217.3	+20.7
6	223.6	1.84	228.9	+5.3
7	256.1	0.05	291.1	+35.0
8	312.7	1.67	327.4	+14.7
9	346.8	0.88	351.9	+5.2
10	410.0	2.41	415.2	+5.2
11	433.7	3.20	442.2	+8.4
12	436.5	1.86	445.4	+8.9
13	526.8	3.29	533.1	+6.2
14	528.3	1.92	538.3	+10.0
15	581.9	0.70	591.5	+9.6
16	585.4	3.49	600.4	+15.0
17	642.1	9.44	646.2	+4.0
18	642.7	0.07	658.5	+15.9
19	758.4	15.18	764.7	+6.3
20	761.2	15.95	773.0	+11.8
21	776.1	18.55	791.9	+15.8
22	851.2	8.60	867.2	+16.0
23	857.0	21.04	874.5	+17.5
24	862.5	31.69	879.0	+16.4
25	888.1	12.83	907.0	+18.9
26	915.3	53.48	926.2	+11.0
27	958.3	1.92	990.4	+32.0
28	990.2	0.02	1005.8	+15.6
29	995.1	4.42	1020.8	+25.7
30	1055.8	7.93	1062.8	+7.0
31	1087.3	39.32	1101.8	+14.5
32	1164.5	27.49	1161.1	-3.4
33	1183.0	0.72	1173.0	-10.0
34	1188.9	10.27	1194.8	+5.8
35	1207.3	59.93	1212.0	+4.8
36	1220.0	18.37	1222.3	+2.4
37	1237.5	4.98	1239.5	+1.9
38	1285.5	47.63	1285.5	+0.0
39	1312.6	240.75	1314.6	+2.0
40	1388.0	51.79	1383.9	-4.1
41	1404.7	14.59	1409.0	+4.3
42	1417.8	5.67	1422.5	+4.7
43	1475.5	26.71	1487.7	+12.2
44	1495.0	33.99	1508.6	+13.5
45	1517.5	15.57	1532.0	+14.5
46	1523.1	5.75	1536.6	+13.5
47	1534.7	34.52	1546.8	+12.1
48	1553.4	45.68	1582.3	+29.0
49	1614.9	26.42	1648.9	+34.0
50	1661.1	109.56	1687.6	+26.4
51	1683.9	77.05	1729.5	+45.6
52	3027.5	62.87	3063.4	+35.9
53	3088.4	41.13	3136.4	+48.0
54	3160.1	26.25	3203.2	+43.1
55	3182.1	1.17	3225.6	+43.5
56	3194.3	15.03	3237.5	+43.2
57	3207.2	26.37	3250.2	+43.0
58	3211.1	7.35	3254.3	+43.2
59	3226.8	8.99	3270.2	+43.3
60	3248.5	0.93	3292.7	+44.2

Second route

Analytic Hessian (pyscf, grid 99/590) against the corpus finite differences: b3lyp max |Δω| 1 cm⁻¹; wb97x max |Δω| 22 cm⁻¹.

Provenance

Releases: none yet
Entered the corpus as: cores with one or two substituents, enumerated from the parents (layer B)
Run: ubuntu-32gb-hel1-16, 2026-09-27 18:28:52 → 2026-09-27 19:22:25, 3212 s, peak 4.27 GB, deck 9e27bf8e9348
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