# Possible ionization and fragmentation of chemicals

Is there any generic method where I can know/calculate/generate the possible ionization and fragmentation of a specific chemical, for example, hydrogen chloride and water?

This question is actually related to the mass spectrometer, where I am asked to identify the possible species/ions of a sample. Therefore I would like to know if there's any method to know (calculate) the outcome without memorising everything, for example the outcome of HCl.

• Agreeing with Mithoron, we may mean at least two things when we talk about ionization. First, we may mean the conversion of neutral molecules into ions by the acquisition or loss of electrons, for example in a redox process or in a mass spectrometer: $$\ce{ CH4 -> CH4+ + e-}$$ Second, we may mean reaction of a neutral molecule (often with the solvent) to produce ions: $$\ce{ HCl + H2O -> H3O+ + Cl-}$$ The word fragmentation in your title makes me think you want the first type of ionization, but the example of HCl in water makes me think you want the second type. Could you clarify? – Ben Norris May 21 '15 at 3:10
• Do you want to predict outcome or analyze it? In case of HCl there's not much to predict - you get HCl+ and it fragmentates into H and Cl+ or H+ and Cl atom. MS is rather used to identify unknown more complicated compounds. – Mithoron May 23 '15 at 13:27