hess controls in .oqp¶
.oqp control reference
Use canonical routes and controls in input files. Raw names
identify implementation storage. A control without an accepted canonical
spelling is not available in .oqp files.
The hess section controls Hessian, frequency, and thermochemistry
workflows.
Keywords¶
type¶
Use the physical route or primary calculation for this control; see the canonical spelling and ownership. Do not write this raw storage key as a separate input section.
| Field | Value |
|---|---|
| Type | string |
| Default | auto |
| Values | auto, numerical, analytical |
| Used by | Hessian dispatch |
Selects the Hessian method:
auto(the default): the native analytical Hessian for ground-state HF/DFT runs (RHF/RKS, UHF/UKS, ROHF/ROKS).- It falls back to the numerical finite-difference Hessian for excited states and when the run uses something the analytical kernel does not differentiate.
- Those cases are PCM solvent, QM/MM embedding, an ODP bias, scalar
relativity, meta-GGA or double-hybrid functionals, fractional occupations
(
pfon), basis functions with L >= 4 (or a basis that cannot be inspected), a system without virtual orbitals, and the numerical-only optionssymmetry_uniqueandrestart. - The choice and its reason are written to the log.
numerical: forces the finite-difference Hessian.analytical: requests the analytical Hessian. The input checker rejects it where the analytical path is not available.
state¶
Use the physical route or primary calculation for this control; see the canonical spelling and ownership. Do not write this raw storage key as a separate input section.
| Field | Value |
|---|---|
| Type | integer |
| Default | 0 |
| Used by | Hessian target state |
HF/DFT Hessians use state 0. TDHF-family Hessian workflows use positive
excited-state indices.
dx¶
Use the physical route or primary calculation for this control; see the canonical spelling and ownership. Do not write this raw storage key as a separate input section.
| Field | Value |
|---|---|
| Type | float |
| Default | 0.01 |
| Used by | numerical Hessian displacement |
Finite-difference step size for numerical Hessians.
nproc¶
Use the physical route or primary calculation for this control; see the canonical spelling and ownership. Do not write this raw storage key as a separate input section.
| Field | Value |
|---|---|
| Type | integer |
| Default | 1 |
| Used by | numerical Hessian workers |
Worker count for numerical Hessian calculations. Must be at least 1.
read¶
Use the physical route or primary calculation for this control; see the canonical spelling and ownership. Do not write this raw storage key as a separate input section.
| Field | Value |
|---|---|
| Type | boolean |
| Default | False |
| Used by | Hessian restart/input |
Reads an existing .hess.json sidecar where the workflow supports it. Current
sidecars carry a versioned state/model-configuration signature and the atom,
geometry, and isotopic-mass identity. OpenQP rejects unsigned older files or mismatches rather
than silently reusing a Hessian or vibrational data from another calculation;
rerun with read=False to generate a current sidecar.
restart¶
Use the physical route or primary calculation for this control; see the canonical spelling and ownership. Do not write this raw storage key as a separate input section.
| Field | Value |
|---|---|
| Type | boolean |
| Default | False |
| Used by | numerical Hessian restart |
Continues an interrupted numerical Hessian workflow.
Native TS/IRC drivers reject restart=True while their displaced-gradient
artifacts lack geometry/model signatures. Use it only for the standalone
numerical Hessian workflow; native TS/IRC initial Hessians are recomputed.
temperature¶
Use the physical route or primary calculation for this control; see the canonical spelling and ownership. Do not write this raw storage key as a separate input section.
| Field | Value |
|---|---|
| Type | float list |
| Default | 298.15 |
| Used by | thermochemistry |
Temperature or temperatures, in Kelvin, for thermochemical analysis. Values must be positive.
clean¶
Use the physical route or primary calculation for this control; see the canonical spelling and ownership. Do not write this raw storage key as a separate input section.
| Field | Value |
|---|---|
| Type | boolean |
| Default | False |
| Used by | temporary Hessian files |
Removes temporary Hessian files where supported.
symmetry_unique¶
Use the physical route or primary calculation for this control; see the canonical spelling and ownership. Do not write this raw storage key as a separate input section.
| Field | Value |
|---|---|
| Type | boolean |
| Default | False |
| Used by | numerical Hessian displacements |
When enabled for a symmetric molecule, displaces one atom from each symmetry-equivalent atom orbit and reconstructs the remaining numerical Hessian rows with the detected abelian symmetry operations. OpenQP detects the point group again at the current reference geometry and proves atom-orbit coverage before launching displaced-gradient jobs.
If symmetry is absent, detection fails, the tolerance is too loose relative to
dx, or complete orbit coverage cannot be established, OpenQP reports the
reason and safely uses the full displacement set. The option does not enable
integral symmetry reduction in the displaced child calculations.