[oqp]¶
The [oqp] section stores controls for the native OpenQP optimizer. Concise
.oqp geometry drivers select this engine automatically and route their native
options here; no lib selector is used. Traditional sectioned .inp files may
still select it explicitly with [optimize] lib=oqp.
Keywords¶
coordsys¶
| Field | Value |
|---|---|
| Type | string |
| Default | auto |
| Used by | native optimizer coordinates |
Coordinate system for the native optimizer. auto selects delocalized internal
coordinates (DLC) for minimum, TS, MECI, MECP, TCI, NEB, IRC, and MEP
calculations. The DLC basis must span the complete molecular vibrational space
(3N-6 for a non-linear isolated system); otherwise OpenQP uses its safer
coordinate-recovery sequence. Molecular complexes are supplemented with
interfragment distances when their primitive internal-coordinate metric is
poorly conditioned. Explicit tric, ric, and Cartesian selections remain
available as expert overrides.
trust¶
| Field | Value |
|---|---|
| Type | float |
| Default | 0.2 |
| Used by | optimizer trust radius |
Initial trust radius.
trust_max¶
| Field | Value |
|---|---|
| Type | float |
| Default | 0.5 |
| Used by | optimizer trust radius |
Maximum trust radius.
freeze¶
| Field | Value |
|---|---|
| Type | string |
| Default | empty |
| Used by | native constrained minimum optimization |
Freezes each listed atom-pair distance at its value in the input geometry.
Indices are one-based. Use distance(i,j) or the short r(i,j) spelling, and
separate multiple pairs with semicolons:
[oqp]
freeze=distance(1,2);distance(2,3)
In concise input, place the same expression directly in opt(...), for example
opt(S0,freeze="distance(1,2)"). Current native constraints are limited to
frozen distances and minimum searches.
follow¶
| Field | Value |
|---|---|
| Type | integer |
| Default | 0 |
| Used by | mode following |
Mode-following selector for transition-state style steps.
init_hessian¶
| Field | Value |
|---|---|
| Type | string |
| Default | model |
| Values | model, numerical, analytical |
| Used by | native transition-state optimization |
Initial Hessian policy for native P-RFO transition-state searches. model
uses the inexpensive internal-coordinate model Hessian. numerical and
analytical calculate a real Cartesian Hessian for the selected state before
the first TS step. In concise input, use
ts(S0,hessian=model|numerical|analytical).
spring¶
| Field | Value |
|---|---|
| Type | float |
| Default | 0.05 |
| Used by | NEB |
NEB spring constant.
climb¶
| Field | Value |
|---|---|
| Type | boolean |
| Default | True |
| Used by | NEB |
Enables climbing-image NEB behavior.
fmax¶
| Field | Value |
|---|---|
| Type | float |
| Default | 2.0e-3 |
| Used by | NEB convergence |
NEB force threshold.
frms¶
| Field | Value |
|---|---|
| Type | float |
| Default | 2.0e-3 |
| Used by | NEB convergence |
RMS force threshold over all movable NEB images. A native band converges only
when both fmax and frms are satisfied.
climb_fmax¶
| Field | Value |
|---|---|
| Type | float |
| Default | 0.05 |
| Used by | climbing-image NEB activation |
Relax-then-climb threshold. Native NEB enables its climbing image after the
ordinary band maximum force falls below this value. When climb=True, it must
be greater than or equal to fmax; otherwise the ordinary band could satisfy
the final threshold before climbing-image activation.
neb_dt¶
| Field | Value |
|---|---|
| Type | float |
| Default | 0.5 |
| Used by | NEB propagation |
NEB FIRE integration step. Concise .oqp accepts dt as the preferred public
spelling and lowers it to neb_dt.
maxmove¶
| Field | Value |
|---|---|
| Type | float |
| Default | 0.2 |
| Used by | NEB image updates |
Maximum NEB image displacement per step.
align¶
| Field | Value |
|---|---|
| Type | boolean |
| Default | True |
| Used by | NEB endpoint preparation |
Rigidly aligns the product endpoint to the reactant with a proper Kabsch rotation before interpolation, removing overall translation and rotation.
opt_ends¶
| Field | Value |
|---|---|
| Type | boolean |
| Default | True |
| Used by | NEB endpoints |
Optimizes NEB endpoints when true.
end_fmax¶
| Field | Value |
|---|---|
| Type | float |
| Default | 1.0e-3 |
| Used by | NEB endpoint convergence |
Endpoint force threshold.
neb_output¶
| Field | Value |
|---|---|
| Type | string (path) |
| Default | empty |
| Used by | NEB final-path output |
Path for the final multi-frame NEB XYZ file. Each frame includes the image
energy in Hartree. If empty, OpenQP writes <project>_neb.xyz in the log
directory. Concise .oqp input uses the public spelling output="path.xyz".
irc_step¶
| Field | Value |
|---|---|
| Type | float |
| Default | 0.1 |
| Used by | IRC |
IRC step size.
irc_direction¶
| Field | Value |
|---|---|
| Type | string |
| Default | forward |
| Used by | IRC |
IRC direction.
mep_step¶
| Field | Value |
|---|---|
| Type | float |
| Default | 0.1 |
| Used by | MEP |
MEP step size.
path_gtol¶
| Field | Value |
|---|---|
| Type | float |
| Default | 1.0e-4 |
| Used by | native IRC and MEP convergence |
Euclidean-norm threshold on the mass-weighted gradient used to stop native IRC
and MEP path tracing. Concise .oqp exposes this value as gtol, for example
irc(S0,gtol=1e-4) or mep(S0,gtol=1e-4).