naphthalene+CH3+NO2 C11H9NO2

B_5bf791b132 · SMILES Cc1ccc2ccccc2c1[N+](=O)[O-] · InChIKey IZNWACYOILBFEG-UHFFFAOYSA-N

Cheap level done imaginary mode, second route pending

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

35 infrared-active bands (500–3500 cm⁻¹); the strongest at 1644 cm⁻¹ (6.1 µm), 244 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 — 2026-09-29, ubuntu-32gb-hel1-16
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)

63 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	-70.0	0.05	-44.9	+25.1
2	47.6	0.57	79.3	+31.7
3	90.7	1.11	112.0	+21.4
4	116.1	0.38	133.9	+17.8
5	154.4	3.79	160.8	+6.3
6	193.2	0.23	206.0	+12.8
7	251.1	2.76	253.9	+2.9
8	258.9	0.02	270.8	+11.9
9	371.4	1.03	377.3	+6.0
10	379.6	0.69	395.0	+15.4
11	427.1	0.64	432.6	+5.5
12	457.5	5.55	468.3	+10.8
13	475.0	1.90	484.3	+9.2
14	508.3	0.09	518.1	+9.7
15	538.5	1.04	542.8	+4.3
16	594.8	1.08	608.3	+13.5
17	660.7	10.61	667.2	+6.6
18	689.6	4.29	707.0	+17.4
19	707.9	0.85	718.3	+10.3
20	746.3	9.51	764.7	+18.4
21	754.6	11.96	765.1	+10.5
22	784.0	13.92	798.6	+14.6
23	807.3	20.03	820.9	+13.5
24	827.9	28.87	842.3	+14.4
25	873.3	7.91	888.5	+15.2
26	877.9	13.78	891.1	+13.3
27	945.1	0.84	956.0	+10.9
28	950.8	0.15	981.9	+31.1
29	967.2	0.45	1000.8	+33.6
30	991.9	0.25	1020.9	+29.1
31	1026.4	0.92	1038.0	+11.5
32	1056.0	1.35	1067.2	+11.2
33	1073.1	2.36	1075.8	+2.8
34	1078.1	2.29	1090.5	+12.4
35	1178.2	0.06	1173.3	-4.9
36	1194.0	1.82	1187.3	-6.7
37	1197.6	0.60	1202.2	+4.6
38	1250.6	2.87	1242.8	-7.8
39	1263.3	6.08	1276.9	+13.6
40	1302.2	8.13	1309.5	+7.4
41	1386.7	7.72	1387.2	+0.5
42	1409.8	12.49	1412.2	+2.4
43	1415.0	0.56	1420.7	+5.7
44	1439.1	74.75	1451.9	+12.8
45	1444.2	17.80	1479.7	+35.5
46	1475.4	3.63	1494.5	+19.1
47	1511.4	22.79	1518.1	+6.7
48	1518.5	0.70	1530.1	+11.6
49	1527.8	6.97	1537.6	+9.8
50	1564.2	14.63	1593.0	+28.7
51	1622.7	0.26	1657.6	+34.9
52	1643.8	244.01	1671.3	+27.5
53	1661.7	6.22	1690.3	+28.5
54	1686.2	2.32	1734.1	+47.9
55	3055.6	15.47	3089.9	+34.2
56	3111.7	6.69	3161.1	+49.4
57	3143.1	12.77	3189.8	+46.7
58	3184.4	1.01	3228.0	+43.6
59	3186.9	3.91	3230.0	+43.1
60	3195.9	7.13	3238.6	+42.7
61	3203.9	21.53	3246.8	+43.0
62	3207.7	21.21	3250.3	+42.7
63	3217.6	14.83	3259.8	+42.2

Second route

Analytic Hessian (pyscf, grid 99/590) against the corpus finite differences: b3lyp max |Δω| 4 cm⁻¹; wb97x max |Δω| 81 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, 2026-09-29 19:24:43 → 2026-09-29 20:27:59, 3795 s, peak 4.84 GB, deck 9e27bf8e9348
Imaginary modes: B3LYP 1, ωB97X 1
Cheap-level band heights: dipole derivatives dipole_b3lyp_cphf.npz, Hessian hessian_b3lyp.npz
Source files: corpus factory · manifest