QC Thermochemistry

Ideal-gas thermochemistry from quantum chemical frequencies: zero-point energy, enthalpy, entropy, Gibbs energy, and heat capacity on a temperature grid, with Grimme / Head-Gordon quasi-RRHO corrections for soft modes. Species with a standard enthalpy of formation also get two-range NASA-7 polynomials as a Cantera species entry. Up to 200 structures of up to 200 atoms each.
0 structures ready
Estimated minimum cost: $—

Examples

Optimized structures

Paste or upload the optimized geometries from an xTB / CREST frequency run (structures.sdf) or a PySCF frequency run (geometries.sdf). Each record's molecule and structure index tags join it to its rows in the vibrations table; moments of inertia and isotope masses come from the geometry.

or drop a file here

Harmonic frequencies

Upload the vibrations.csv from the same frequency run as the structures. Imaginary modes appear as negative wavenumbers.

or drop a file here

Thermochemistry options

Temperatures run from 10 to 5000 K (at most 500 points); 298.15 K is always included.

Species and NASA-7

One row per molecule in the structures (conformers of a molecule share it). Set the rotational symmetry number and spin multiplicity; blank cells use σ = 1 and the structure's unpaired-electron tag. Molecules with a standard enthalpy of formation get a two-range NASA-7 fit (from their lowest-G conformer) and a Cantera species entry anchored to ΔHf and S at 298.15 K.

Add tagged structures above to set per-molecule values.