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Orbital and Vibrational Output

Source access and public downloads

Repository paths identify files in the licensed engine source; they are not public downloads. For freely downloadable .oqp inputs and results, see Worked Examples.

OpenQP can write molecular orbitals, vibrational normal modes, and state-specific MRSF-EKT Dyson orbitals in portable JSON and Molden formats. These files can be opened together in OpenqpView so the same calculation can display both MO surfaces and animated normal modes. Files are processed locally by the browser.

Orbitals during a dynamics run

The SCF also writes a molecular-orbital table (orbital energies, and the coefficients at verbose = 2) to the log after every call, which for runtype = md or namd means once per step of the trajectory. Those run types therefore default scf.verbose to 0, which suppresses that table; set verbose = 2 to get it back. The machine-readable orbitals described on this page are unaffected.

Portable JSON

Set guess.save_mol=True to retain the full same-stem .json calculation file. When the AO basis uses an ordering supported by Molden, the JSON includes:

  • basis_set: contracted shells, Molden-normalized primitive coefficients, spherical/Cartesian convention, and AO ordering;
  • molecular_orbitals: alpha and, where applicable, beta energies, occupancies, and AO coefficients;
  • dyson_orbitals: state-specific IP/EA AO coefficients, labels, parent state, electron binding energy, and pole strength for MRSF-EKT calculations; and
  • frequency_modes: frequencies in cm⁻¹ and mass-unweighted Cartesian normal mode displacements when a frequency calculation has completed.

Hessian workflows also write <project>.hess.json. It contains the Hessian, frequencies, normal modes, IR intensities, Raman activities, atoms, geometry, and—when available—the same portable basis and MO blocks. Consequently, either the full .json or .hess.json can provide both the molecular orbitals and the vibrational view.

High angular-momentum H/I shells and mixed Cartesian/spherical bases remain valid OpenQP calculations, but their optional portable viewer blocks are omitted when no unambiguous Molden AO ordering is available.

Combined Molden MO and frequency file

A completed Hessian workflow writes <project>.freq.molden. When the basis and SCF orbitals support Molden ordering, this is a combined file with:

  • [Atoms], [GTO], spherical-harmonic markers, and [MO];
  • [FREQ] and standard one-value-per-mode [INT] IR intensities;
  • optional [RAMAN] activities; and
  • [FR-COORD] and [FR-NORM-COORD] normal-mode geometry and displacements.

The standard Molden sections keep the file usable by other Molden readers, including applications that ignore the optional [RAMAN] extension. If the basis cannot be represented in portable Molden ordering, OpenQP safely falls back to a frequency-only Molden file.

State-specific MRSF-EKT Dyson Molden

For MRSF-EKT, enable scf.save_molden=True. After the EKT kernel finishes, OpenQP writes a dedicated dyson Molden file. Each orbital is labeled by channel and root, for example Dyson-IP-state-1 or Dyson-EA-state-2; its energy records the EKT eigenvalue and its occupancy records the pole strength. OpenqpView exposes these labels as individually selectable Dyson orbitals.

The H₂O IP example enables both JSON and Molden exports and includes generated SCF and Dyson Molden results:

examples/other/h2o_rohf_mrsf_ekt_ip_6-31g_bhhlyp.oqp

Minimal input settings

.oqp Hessian output with MO data:

dft/bhhlyp/6-31g* hess(S0,type=analytical,clean=true) guess(save_mol=true)
geom="h2o.xyz"

Canonical .oqp MRSF-EKT output:

mrsf(nstate=10)/bhhlyp/6-31g ekt guess(save_mol=true)
geom="molecule.xyz"

Scientific references

Vibrational and magnetic properties; Excited-state analysis and ionization; Software libraries and data formats.