imidazole+CH3 C4H6N2

B_04927bf562 · SMILES Cc1ncc[nH]1 · InChIKey LXBGSDVWAMZHDD-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.

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

30 vibrational modes; imaginary modes negative. Shift = ωB97X − B3LYP.

Band heights are not computed for this molecule yet (no dipole derivatives); positions only, at unit height. High wavenumbers on the left; the table below is the same data.

#	B3LYP (cm⁻¹)	ωB97X (cm⁻¹)	shift
1	82.2	84.7	+2.5
2	251.2	262.6	+11.4
3	347.8	351.4	+3.5
4	498.4	543.8	+45.4
5	642.0	657.7	+15.6
6	679.1	687.1	+8.0
7	687.9	706.0	+18.1
8	721.2	743.4	+22.2
9	848.9	878.7	+29.9
10	928.4	935.9	+7.6
11	974.4	981.1	+6.7
12	1015.2	1020.6	+5.4
13	1075.3	1079.9	+4.6
14	1109.5	1119.6	+10.1
15	1144.2	1151.1	+6.9
16	1192.5	1207.8	+15.3
17	1284.8	1297.4	+12.6
18	1404.5	1423.1	+18.6
19	1441.0	1453.6	+12.5
20	1457.2	1477.8	+20.6
21	1514.2	1518.2	+4.0
22	1515.5	1535.9	+20.5
23	1538.3	1554.2	+15.9
24	1609.5	1638.4	+28.9
25	3041.3	3077.7	+36.4
26	3088.4	3139.9	+51.5
27	3159.6	3204.6	+44.9
28	3260.6	3300.7	+40.1
29	3292.1	3333.0	+40.9
30	3646.1	3696.8	+50.8

Structure

2D depiction from the SMILES.

Status ladder

Listed
Cheap level done — 2026-09-27, ubuntu-32gb-hel1-14
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.

Second route

Analytic Hessian (pyscf, grid 99/590) against the corpus finite differences: b3lyp max |Δω| 0 cm⁻¹; wb97x max |Δω| 31 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, 2026-09-27 12:30:13 → 2026-09-27 12:36:57, 403 s, peak 1.56 GB, deck 9e27bf8e9348
Imaginary modes: B3LYP 0, ωB97X 0
Source files: corpus factory · manifest