Th UKRMOL+ codes are freely available from Zenodo. You have to install both in and outer-region codes. You can calculate cross sections for various processes including the electronic-excitation. However, these are sophisticated codes which require accurate input files. For electron-impact ionization cross section, you can use the standard binary- encounter Bethe (BEB) method. There is a simple formula for this. But you have to have your molecule's orbital data for this to work.