gabedit and c2x

Gabedit is designed to be used as a GUI front-end to various quantum chemistry packages. However, it can process output from runs it has not controlled.

Its most useful input format for volumetric data is the cube format, and it is unusually fussy about this. It will not read correctly .cube files generated by versions of c2x prior to 2.32, and it insists that molecular orbitals are stored in the multi dataset version of cube files, even if there is only one of them.

For this example, a suitable input file was prepared with

$ c2x -b=6 --mocube ethene.check ethene.cube

and gabedit started. One then needs to click on the tiny icon icon in the toolbar (its tooltip text is Display Geometry / Orbitals / Density / Vibration). This produces a large, black window.

A right-click in this window produces a large menu, from which one can select Cube&Grid, Load Gaussian cube, Orbitals file. Then one needs to navigate to the right place from a chooser which appears to ignore its current directory, and select a suitable cube file. It immediately prompts for an isovalue. A value of 0.3 was used, and the positive and negative isosurfaces were automatically generated and coloured as below (after a little rotation and zooming).

Ethene pi bond in gabedit

Charge densities can be viewed with Cube&Grid, Load Gaussian cube, Density only file, and these can be generated with c2x's --cube option, but the output from c2x 2.31 and earlier will not be read correctly.