Welcome to IOData’s documentation!¶

IOData is a free and open-source Python library for parsing, storing, and converting various file formats commonly used by quantum chemistry, molecular dynamics, and plane-wave density-functional-theory software programs. It also supports a flexible framework for generating input files for various software packages.

Please use the following citation in any publication using IOData library:

“IOData: A python library for reading, writing, and converting computational chemistry file formats and generating input files.”, T. Verstraelen, W. Adams, L. Pujal, A. Tehrani, B. D. Kelly, L. Macaya, F. Meng, M. Richer, R. Hernandez‐Esparza, X. D. Yang, M. Chan, T. D. Kim, M. Cools‐Ceuppens, V. Chuiko, E. Vohringer‐Martinez,P. W. Ayers, F. Heidar‐Zadeh, J Comput Chem. 2021; 42: 458–464.

Copy-pasteable citation records in various formats are provided in How to Cite IOData.

For the list of file formats that can be loaded or dumped by IOData, see Supported File Formats. The two tables below summarize the file formats and features supported by IOData.

Code	Definition
L	loading is supported
D	dumping is supported
(d)	attribute may be derived from other attributes
R	attribute is always read
r	attribute is read if present
W	attribute is always written
w	attribute is is written if present

Attribute	fchk: LD	json_qcschema: LD	qchemlog: L	extxyz: L	wfx: LD	mwfn: L	gamess: L	wfn: LD	pdb: LD	molden: LD	cp2klog: L	orcalog: L	molekel: LD	mol2: LD	locpot: L	gromacs: L	fcidump: LD	cube: LD	chgcar: L	charmm: L	sdf: LD	poscar: LD	xyz: LD	gaussianinput: L	gaussianlog: L
`atcharges`	Rw	.	.	.	.	.	.	.	.	.	.	.	rw	Rw	.	.	.	.	.	.	.	.	.	.	.
`atcoords`	Rw	RW	R	r	RW	R	R	RW	RW	RW	R	R	RW	RW	R	R	.	RW	R	R	RW	RW	RW	R	.
`atcorenums` (d)	RW	Rw	.	.	W	R	.	.	.	Rw	R	.	.	.	.	.	.	Rw	.	.	.	.	.	.	.
`atffparams`	.	.	.	.	.	.	.	.	Rw	.	.	.	.	Rw	.	R	.	.	.	R	.	.	.	.	.
`atfrozen`	rw	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.
`atgradient`	rw	.	.	r	Rw	.	R	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.
`athessian`	rw	.	r	.	.	.	R	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.
`atmasses`	rw	rw	R	r	.	.	R	.	.	.	.	.	.	.	.	.	.	.	.	R	.	.	.	.	.
`atnums`	RW	RW	R	r	RW	R	R	RW	RW	RW	R	R	RW	RW	R	.	.	RW	R	.	RW	RW	RW	R	.
`basisdef`	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.
`bonds`	.	rw	.	.	.	.	.	.	rw	.	.	.	.	.	.	.	.	.	.	.	Rw	.	.	.	.
`cellvecs`	.	.	.	r	.	.	.	.	.	.	.	.	.	.	R	R	.	R	R	.	.	RW	.	.	.
`charge` (d)	w	RW	.	r	W	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.
`core_energy`	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	Rw	.	.	.	.	.	.	.	.
`cube`	.	.	.	.	.	.	.	.	.	.	.	.	.	.	R	.	.	RW	R	.	.	.	.	.	.
`energy`	rw	r	R	r	Rw	R	R	Rw	.	.	R	R	.	.	.	.	.	.	.	.	.	.	.	.	.
`extcharges`	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.
`extra`	rw	rw	R	r	Rw	R	.	Rw	RW	.	.	R	.	.	.	R	.	.	.	R	.	.	.	.	.
`g_rot`	.	rw	R	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.
`lot`	Rw	r	R	.	w	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.
`mo`	Rw	.	R	.	RW	R	.	RW	.	RW	R	.	RW	.	.	.	.	.	.	.	.	.	.	.	.
`moments`	rw	.	.	.	.	.	.	.	.	.	.	R	.	.	.	.	.	.	.	.	.	.	.	.	.
`natom` (d)	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.
`nelec` (d)	.	R	.	.	.	.	.	.	.	.	.	.	.	.	.	.	Rw	.	.	.	.	.	.	.	.
`obasis`	R	r	.	.	RW	R	.	RW	.	RW	R	.	RW	.	.	.	.	.	.	.	.	.	.	.	.
`obasis_name`	Rw	r	R	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.
`one_ints`	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	RW	.	.	.	.	.	.	.	r
`one_rdms`	rw	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.
`run_type`	R	.	R	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.
`spinpol` (d)	.	RW	.	.	w	.	.	.	.	.	.	.	.	.	.	.	Rw	.	.	.	.	.	.	.	.
`title`	R	rw	.	R	Rw	R	R	Rw	rw	rw	.	.	.	rw	R	R	.	w	R	r	Rw	Rw	Rw	R	.
`two_ints`	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	RW	.	.	.	.	.	.	.	r
`two_rdms`	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.

Welcome to IOData’s documentation!¶

User Documentation¶

Developer Documentation¶

API Reference¶

Indices and tables¶