.. _prefactor:

=========
Prefactor
=========


[Prefactor] Options
-------------------

**all_free_atoms**: Account for all free atoms when determining the prefactor.

    default: ``false``
    
**filter_scheme**: Determines how to filter the atoms for use in the prefactor calculation.
The two options are "cutoff", which includes atoms that move more than "min_displacement",
and "fraction", which includes the atoms that make up "filter_fraction" of the total motion, 
prioritizing the atoms that move the most.

    default: ``fraction``
    
**filter_fraction**: When using filter_scheme "fraction", the atoms that move the most will be
included in the prefactor calculation, limited to the number that make up "filter_fraction" of
the total motion.

    default: ``0.9``

**min_displacement**: Minimum amount that an atom has to move to be included in
the Hessian calculation. Used only with filter_scheme "cutoff"

    default: ``0.25``

**within_radius**: Atoms within this radius of moving atoms are included in the
Hessian. Used only with filter_scheme "cutoff"

    default: ``3.3``

**default_value**: Calculate prefactor if zero, otherwise use given value
instead of doing a full prefactor calculation.

    default: ``0``

**min_value**: Minimum value for a reasonable prefactor.

    default: ``1e+9``


**max_value**: Maximum value for a reasonable prefactor.

    default: ``1e+21``

**configuration**: When EON runs as a prefactor job the eigenfrequencies 
will be determined for the stated configuration.

    default: ``reactant``

    options:
        ``reactant``
        ``saddle``
        ``product``