The complete chemistry-paper SI for a small molecule.

Pick a molecule, pick a method, click run. The page optimizes the geometry and computes everything an experimental SI table would report — energy, gradients, IR + Raman + UV-vis spectra, dipole + polarizability + hyperpolarizability tensors, charges + bond orders, full ideal-gas thermochemistry at 298 K, and ionization potentials. Every number is computed in your browser tab; no server. Reference values shown next to each panel where they're available.

Basis set is STO-3G — the smallest workable basis, fast enough that the full pipeline (SCF + geom-opt + Hessian + IR/Raman + polarizability + β + UV-vis + thermo + IP) finishes in tens of seconds for triatomics. Properties at STO-3G underestimate polarizabilities by ~3× vs experiment; that's a known basis limitation, not a bug. cc-pVDZ / aug-cc-pVDZ versions live in the test suite.