| Abstract: | A Method is presented whereby product organic ions formed as the result of fragmentation of metastable ions can be selected on the basis of their internal energies. The method requires requires angular collimation of the beam of reactant ions issuing from the ion source and that the fragmentation of the metastable ions is studied in the first field free region of a reversed geometry double focusing mass spectrometer. The product ions that make up the metastable peak are allowed to fall on the intermediate resolving slit and, by adjusting the magnet current over a small range, ions contained in different regions of the peak can be allowed into the second field free region. It is shown that the position of an ion within the metastable peak correlates with its internal energy, ions near the edges of the peak being the least excited. The ions entering the second field free region can be investigated by collisional activation. This has been done for molecular ions of p-chlorophenol, methylbenzoate, benzaldehyde, m-chlorotoluene and n-butane. The in which the collision induced fragmentation pattern varies with internal energy of the ions is illustrated. |
