Thermodynamics and kinetics answered — in the same conversation
Without a separate thermodynamics calculation, without a separate NEB setup, without two computational tools and two sets of outputs to reconcile. Provide reactant and product SMILES. Get the full thermochemistry and, if needed, the activation barrier.
“Is this Diels-Alder thermodynamically feasible at 298 K, and what's the activation barrier?”
How it works
Provide reactant and product SMILES
predict_reaction_thermodynamics returns ΔG, ΔH, TΔS, and K_eq in one call. Confidence tiering: high (all-organic), medium (non-standard elements), low (transition metals — flag, not block).
Add kinetics if needed
Provide pre-optimized XYZ geometries to find_transition_state. CI-NEB locates the activation barrier, minimum energy path, forward and reverse barriers, and transition state geometry.
Confirm with vibrational analysis
run_qm_hessian confirms the transition state (one imaginary frequency) or true minimum (none). Returns ZPE and Gibbs corrections. Imaginary frequencies flag structures not at true minima.
Proof
Butadiene + ethylene → cyclohexene: ΔG = -48.8 kcal/mol, K_eq = 5.7×10³⁵ (spontaneous). Methane combustion: ΔG = -289.7 kcal/mol (effectively irreversible).
Ethanol dehydration at 298 K: +19.7 kcal/mol (non-spontaneous — consistent with textbook requirement for heat).
HCN → HNC: 59.4 kcal/mol forward barrier, 39.4 reverse, TS geometry attached, 6.7 seconds.
Boundary: predict_reaction_thermodynamics answers can it happen. find_transition_state answers how fast. Neither is valid for transition-metal-catalyzed mechanisms (low confidence tier).
Thermodynamics and kinetics, one pipeline
ΔG + activation barrier. Confidence-tiered. Sign up and check your first reaction.