Software Compatibility

Critic2 can read structures and scalar fields from multiple sources. The amount of information available to critic2 depends on the source file. The table below gives the computational chemistry software with which critic2 can interface, listed in alphabetical order.

The file format is assumed by critic2 based on the extension (although there are keywords to change this behavior). The table gives in the second column the extensions critic2 uses for each format. When the same extension is used for different formats, critic2 will try to guess the correct format from the contents of the file.

The “structures” column gives whether the structure of a molecule, a crystal, or both can be read from the file. A crystal structure must be read with the CRYSTAL keyword and a molecule with the MOLECULE keyword.

The “fields” column gives the information read by critic2 when this file is read as a new scalar field using the LOAD keyword. In this column, “grid” means that the field is available only at the points belonging to a uniform grid, and that the value calculated at any other point is obtained by interpolation. “arbitrary” means that the scalar field read corresponds to whatever the program generated; critic2 will make no assumptions. “rho” means that the electron density is read, and “wfn” means that the wavefunction is read. The latter typically allows calculating values of individual molecular orbitals, energy densities, and other quantities. “basis” means that the basis set is read, which enables the calculation of molecular integrals.

More details about these formats can be found in the documentation for the CRYSTAL, MOLECULE, and LOAD keywords.

Software	Format (extension)	Structures	Fields	Notes
Multiple	cif	crystals
	cube	crystals,molecules	grid,arbitrary
	bincube	crystals,molecules	grid,arbitrary	Binary version of a cube file, generated by critic2
	xyz	molecules		Number of atoms in line 1; line 2 ignored
	mol2	molecules
	pdb	molecules		Used in biochemical applications
abinit	DEN,PAWDEN,ELF,POT,etc.	crystals	grid,arbitrary
ADF	molden	molecules	rho,wfn,basis
aimpac	qub		grid,arbitrary
aiPI	ion	crystals	rho
CASTEP	cell	crystals		CASTEP input file
	geom	crystals		CASTEP output file
	fmt		grid,arbitrary	Generated by CASTEP write_* keywords
Crystal17	out	crystals		Crystal17’s output file
DFTB+	gen	crystals,molecules
	xml	crystals,molecules	rho,wfn	DFTB+’s detailed.xml file (plus bin and hsd)
DMACRYS	dmain	crystals		The DMACRYS main input file
	16	crystals		fort.16 file generated by DMACRYS
	21	crystals		fort.21 file generated by NEIGHCRYS
elk	OUT	crystals		Elk’s GEOMETRY.OUT file
	grid	crystals	grid,arbitrary	Requires a patch to the elk source code
	OUT	crystals	rho,arbitrary	Elk’s STATE.OUT,etc.
FHIaims	in,in.next_step	crystals,molecules		FHIaims geometry.in and geometry.in.next_step
	out,own	crystals,molecules		FHIaims output file
Gaussian	cube	molecules	grid,arbitrary
	wfn,wfx	molecules	rho,wfn
	fchk	molecules	rho,wfn,basis
	log	molecules		Gaussian output file
	gjf,com	molecules		Gaussian input file
	zmat	molecules		z-matrix format
ORCA	molden,molden.input	molecules	rho,wfn,basis
postg	pgout	molecules		postg output file
psi4	molden	molecules	rho,wfn,basis
	fchk	molecules	rho,wfn,basis
	dat	molecules		psi4 output file
Quantum ESPRESSO	out, pwo	crystals		pw.x output file (typically .scf.out or .pwo)
	in, pwi	crystals		pw.x input file (typically .scf.in or .pwi)
	cube	crystals	grid,arbitrary	Generated by pp.x
	pwc	crystals	grid,rho,wfn	Generated by pw2critic.x
SHELX	res	crystals
	ins	crystals		Same format as a res file
SIESTA	STRUCT_IN,STRUCT_OUT	crystals		Input and output structure files
	RHO,BADER,DRHO,LDOS,VT,VH	crystals	grid,arbitrary	Do not contain information about the structure
TINKER	frac	crystals
VASP	POSCAR,CONTCAR,vasp	crystals
	CHGCAR,CHG,ELFCAR,AECCAR*	crystals	grid,arbitrary
WIEN2k	struct	crystals
	clmsum,clmup,clmdn	crystals	rho,arbitrary
Xcrysden	xsf,axsf	crystals	grid,arbitrary