iodata.formats.fchk module

Gaussian FCHK file format.

dump_one(f, data)

Dump a single frame into a Gaussian Formatted Checkpoint file.

Parameters

• f (Textio) – A writeable file object.

• data (IOData) – An IOData instance which must have the following attributes initialized: atnums, atcorenums. If the following attributes are present, they are also dumped into the file: atcharges, atcoords, atfrozen, atgradient, athessian, atmasses, charge, energy, lot, mo, one_rdms, obasis_name, extra, moments.

Notes

None

load_many(lit)

Load a single frame from a XYZ file.

Parameters

lit (LineIterator) – The line iterator to read the data from.

Returns

A dictionary with IOData attributes. The following attributes are guaranteed to be loaded: atcoords, atgradient, atnums, atcorenums, energy, extra, title.

Return type

data

Notes

Trajectories from a Gaussian optimization, relaxed scan or IRC calculation are written in groups of frames, called “points” in the Gaussian world, e.g. to discrimininate between different values of the constraint in a relaxed geometry. In most cases, e.g. IRC or conventional optimization, there is only one “point”. Within one “point”, one can have multiple geometries and their properties. This information is stored in the extra attribute:

• ipoint is the counter for a point

• npoint is the total number of points.

• istep is the counter within one “point”

• nstep is the total number of geometries within in a “point”.

• reaction_coordinate is only present in case of an IRC calculation.

load_one(lit)

Load a single frame from a Gaussian Formatted Checkpoint file.

Parameters

lit (LineIterator) – The line iterator to read the data from.

Returns

A dictionary with IOData attributes. The following attributes are guaranteed to be loaded: atcharges, atcoords, atnums, atcorenums, energy, lot, mo, obasis, obasis_name, run_type, title. The following may be loaded if present in the file: atfrozen, atgradient, athessian, atmasses, one_rdms, extra, moments.

Return type

data

Notes