c2x and PWscf

Quantum Espresso is a GPLed suite of electronic structure codes, and c2x targets PWscf, the DFT component.

From version 2.15, c2x can read and write some data from its input files. Support does not extend to spin-polarised systems (yet).


A file suffix of .in causes c2x to invoke an Abinit reader, which in turn invokes the Quantum Espresso reader if the first line is &control.

Reading of systems with any of the 17 Bravais lattices which QE understands is supported. Just atomic positions, k-points, energy cut-off and title are read.

There seems to be some confusion about the syntax of options on cards. On a line such as


should there be brackets around "angstrom", and should they be square brackets or parentheses? C2x will accept either or none.

When reading namelists, c2x ignores equals signs and commas, and accepts multiple parameters per line. It does not accept a linebreak between a parameter and its value.

.cube files

The .cube files produced by pp.x are in atomic units. They should thus be read with the -U switch. The ionic charges given are the atomic numbers, not the pseudopotential charges, so these need to be modified by hand if calculating dipole moments.


Files are written with no brackets, and with one parameter per line in namelists. The -u flag is recognised for switching the output from Angstrom (default) to Bohr.