Very new user: Calculate the cartesian atomic coordinates for a molecule

[a-jp]

All,

I would like to calculate for a given molecule the cartesian atomic coordinates in Angstroms. Would it be possible to have a working example to do this that would allow me to vary the input molecule and get as an output, ideally in a simple text file, the above?

I would very much appreciate any help here, I am new to the code. I appreciate I will need to understand eventually aspects relating to optimisation options and the model used PM3/PM7. But a working example with trusted defaults would be most welcome.

Many thanks,

[nbehrnd]

What is the file format your molecule of interest is described? Because there are a couple of them, the most elementary the .xyz, where atoms' positions are described in a Cartesian coordinate system with (an implicit) scale in Angstrom. See e.g., openbabel.

If "calculate for a given molecule the cartesian atomic coordinates" refers to a conversion of the underlying file format, openbabel (with its optional gui) might suffice. Examples of conversion are compiled here.

If you seek a GUI to set up a subsequent computation for instance with MOPAC, avogadro and its input generators is one example of a helpful assistant: