Merge pull request #27 from v1j4y/orca_trexio_doc_info

Add orca example.

README.md

@@ -49,6 +49,15 @@ converts data from the `GAMESS_CAS.log` output file of the GAMESS code
 (note also `-t gamess` argument) into the TREXIO file called `trexio_cas.hdf5`
 using `-b hdf5` back end of TREXIO. 
 
+and,
+
+`trexio convert-from -t orca -i data/ORCA.json -b hdf5 trexio_orca.hdf5`
+
+Note that since ORCA AOs and MOs are in spherical coordinates, one needs to convert
+these to cartesian to be able to use `trexio` functions.
+
+`trexio convert-to -t cartesian -o trexio_orca_cart.hdf5 trexio_orca.hdf5`
+
 converts data from the `ORCA.json` output file of the ORCA code
 into the TREXIO file called `trexio_cas.hdf5` using `-b hdf5` back end of TREXIO.