naphthalene+CH3+ethynyl C13H10

B_54b643d16d · SMILES C#Cc1cc2ccccc2cc1C · InChIKey QEDYRXCKIVZNGU-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

41 infrared-active bands (500–3500 cm⁻¹); the strongest at 3495 cm⁻¹ (2.9 µm), 93 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 — 2026-09-30, ubuntu-32gb-hel1-14
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	87.3	0.19	91.5	+4.2
2	114.8	1.29	129.9	+15.1
3	134.2	0.26	148.9	+14.7
4	141.1	0.00	168.0	+26.9
5	225.7	0.11	234.2	+8.5
6	269.5	0.90	274.3	+4.8
7	282.8	0.53	294.3	+11.4
8	376.1	0.10	383.5	+7.4
9	390.2	0.53	401.3	+11.0
10	421.3	1.22	428.9	+7.6
11	447.7	1.34	453.0	+5.3
12	475.4	2.45	486.1	+10.7
13	492.8	6.55	497.4	+4.6
14	549.6	30.11	577.3	+27.8
15	571.4	14.83	602.6	+31.3
16	594.3	0.75	616.1	+21.8
17	631.1	43.55	638.9	+7.8
18	635.3	2.66	660.9	+25.6
19	656.4	0.31	676.8	+20.3
20	701.2	2.63	715.0	+13.9
21	748.3	0.76	754.9	+6.6
22	765.2	31.38	774.5	+9.4
23	777.2	0.14	790.6	+13.4
24	829.0	0.07	838.6	+9.6
25	865.8	0.15	879.0	+13.3
26	896.7	31.80	912.7	+16.0
27	917.3	1.04	926.5	+9.2
28	919.2	0.27	936.4	+17.2
29	956.8	4.01	987.4	+30.6
30	989.2	0.00	1019.5	+30.3
31	1039.2	5.57	1044.0	+4.8
32	1051.6	0.71	1060.7	+9.1
33	1078.4	3.24	1084.7	+6.3
34	1112.0	2.37	1129.0	+17.1
35	1182.2	5.59	1167.0	-15.1
36	1188.0	0.47	1190.0	+2.0
37	1213.4	0.52	1216.3	+2.9
38	1266.5	2.28	1265.4	-1.1
39	1276.3	1.13	1281.7	+5.4
40	1302.4	5.82	1309.5	+7.1
41	1364.4	0.44	1376.3	+12.0
42	1404.7	2.72	1396.5	-8.2
43	1420.7	0.06	1424.8	+4.0
44	1445.4	0.51	1454.5	+9.1
45	1487.3	2.26	1504.0	+16.6
46	1505.1	7.23	1515.0	+9.9
47	1508.5	6.67	1527.5	+19.0
48	1521.3	5.22	1531.0	+9.7
49	1547.5	10.89	1573.3	+25.8
50	1619.2	0.28	1650.7	+31.5
51	1658.5	8.13	1687.5	+29.0
52	1685.1	3.59	1734.4	+49.3
53	2218.9	4.61	2258.1	+39.2
54	3047.9	23.93	3083.2	+35.3
55	3100.7	14.49	3151.3	+50.5
56	3131.1	16.24	3178.6	+47.5
57	3175.0	9.73	3219.9	+44.8
58	3178.7	10.34	3221.7	+43.0
59	3183.1	1.17	3226.5	+43.4
60	3195.9	24.67	3239.1	+43.3
61	3199.1	14.95	3242.2	+43.2
62	3208.8	34.15	3251.6	+42.7
63	3494.7	92.91	3529.3	+34.6

Second route

Analytic Hessian (pyscf, grid 99/590) against the corpus finite differences: b3lyp max |Δω| 1 cm⁻¹; wb97x max |Δω| 19 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-hel1-14, 2026-09-30 12:09:42 → 2026-09-30 13:09:27, 3585 s, peak 4.37 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