CogniChem Application

Vibrational Spectrum Library

Harmonic IR spectra for every conformer of a 3D ensemble from a GFN2-xTB Hessian (after an xTB optimization by default), broadened onto a shared wavenumber grid, plus Boltzmann-weighted ensemble spectra for each molecule from xTB free energies. Up to 200 conformers of up to 200 atoms each.

Job name

0 conformers ready

Resource

Estimated minimum cost: $—

Calculation options

Choose the geometry, implicit solvent (ALPB), and the grid the spectra are broadened onto (at most 4000 points).

Input format

Geometry

Optimization level

Solvent

Charge

Unpaired electrons

Temperature (K)

Line shape

Line width, FWHM (cm⁻¹)

Grid minimum (cm⁻¹)

Grid maximum (cm⁻¹)

Grid step (cm⁻¹)

Conformers

Paste or upload 3D structures, such as a conformer ensemble. Each SDF record is one conformer; conformers with the same structure are grouped into one molecule for the ensemble spectrum. Include explicit hydrogens when the Hessian runs at the input geometry.

or drop a file here

Precomputed vibrations (optional)

Upload the vibrations.csv from an xTB / CREST frequency run to skip the Hessian. The conformers must then be that run's structures.sdf, so each record's molecule and structure indices match the table.

or drop a file here