Input generator

Crystals, surfaces and chains run with riper and need the cell in the coord file.

Unpaired electrons: 0 for a closed shell, 1 for a doublet, 2 for a triplet; EPR needs at least 1.

DFT is the usual start. MP2, CC2, CCSD(T) and RPA add electron correlation at a much higher cost.

Hybrids mix in exact exchange and cost more than GGAs and meta-GGAs.

Adds the van der Waals attraction that most density functionals miss.

Couplings need steep s functions near the nuclei: pcJ-1 or pcJ-2 (H–Ar).

Preselected for speed. For GW, def2-TZVPP is the most useful set: within 0.1 eV of def2-QZVP with about half the basis functions.

Preselected for speed. Correlation energies converge slowly with the basis set: for reliable results use def2-TZVPP or larger; with def2-SVP expect at most a qualitative trend.

Preselected for speed. Coupled-cluster energies converge slowly with the basis set: use def2-TZVPP or larger for results you report; def2-QZVP is the set meant for highly correlated methods.

Preselected for speed. Like MP2, RPA correlation energies converge slowly with the basis set: for reliable results use def2-QZVP.

Preselected for speed. For results you report, def2-TZVP is the recommended choice.

Exact exchange in riper takes odd numbers only and needs a dense mesh (see the notes).

Fermi smearing helps metals and small-gap systems converge.

Example values: set the element, l and U_eff for your system.

Counted in each irreducible representation (in C1: in total).

A subgroup of the structure's point group, kept in the optimization.

ω = 0.057 au ≈ 800 nm.

Empty for all. A coupling is computed when one of its two nuclei is selected: element symbols (C H) or atom numbers (1,3,5-8).

Empty for all. Element symbols (C H) or atom numbers (1,3,5-8).

COSMO puts the molecule in a dielectric continuum; the solvent sets its permittivity ε and the refractive index that excited states use.

No preset path fits this cell; kpath_coord makes one (see the notes).

The band path Γ–M–K–Γ needs a hexagonal cell: a = b, γ = 120°.

The band path needs the fcc primitive cell: a = b = c, α = β = γ = 60°.