Keyword Reference

This chapter is the book-style reference for OpenQP input keywords. Workflow pages show complete input decks; this chapter explains what each keyword means, what type of value it expects, what default the parser applies, and which workflow constraints are enforced by the input checker.

The entries are aligned with these OpenQP source files:

• pyoqp/oqp/molecule/oqpdata.py
• pyoqp/oqp/utils/input_checker.py

How to Read an Entry

Each keyword entry uses the same structure:

Field	Meaning
Type	The parsed value type used by OpenQP.
Default	The value inserted when the keyword is omitted.
Values	Allowed or commonly used values. If validation enforces a finite set, that set is listed.
Used by	The workflows or code paths that normally read the keyword.
Description	The practical meaning of the keyword.
Notes	Interactions with other keywords, limitations, and common mistakes.

Boolean keywords accept ordinary true/false spellings such as true, false, yes, no, 1, and 0 unless a keyword documents a narrower set.

State numbering is workflow dependent. HF/DFT reference-state properties use state 0. Ordinary TDHF/TDDFT state 1 means the first excited state. SF-TDDFT and MRSF-TDDFT state 1 means the lowest spin-flip/MRSF target state, which can be the multiconfigurational ground state.

Method background and literature pointers are collected in References. The keyword pages link there for MRSF-TDDFT, SOC, scalar relativistic correction, and PCM/ddX rather than repeating full bibliographies inside each keyword entry.

Section Index

Section	Purpose
[input]	Global calculation setup, geometry, run type, AO convention, threading.
[guess]	Initial orbitals, restart files, and MO swaps.
[scf]	Reference type, convergence controls, pFON, TRAH, fallback manager.
[dftgrid]	DFT quadrature and hybrid/range-separated functional controls.
[tdhf]	TDHF/TDDFT/SF/MRSF/UMRSF response settings.
[properties]	Gradients, NMR, export, and property requests.
[hess]	Hessian, frequency, and thermochemistry controls.
[nac]	NAC and NACME state-pair controls.
[ekt]	MRSF-EKT IP/EA channel selection.
[optimize]	Target state and optimization convergence controls.
[oqp]	Native optimizer controls.
[geometric]	geomeTRIC optimizer backend controls.
[neb]	NEB product endpoint and image count.
[pcm]	Reference-SCF PCM/ddX settings.
[symmetry]	Point-group metadata and optional symmetry reductions.

Documentation Rule

When an OpenQP pull request changes a default, accepted value, validation rule, or workflow scope, update the matching keyword page in this documentation repository before the next release.