Comparison of collision- versus electron-induced dissociation of sodium chloride cluster cations

The collision-induced dissociation (CID) and electron-induced dissociation (EID) spectra of the [(NaCl)(m)(Na)(n)](n+) clusters of sodium chloride have been examined in a hybrid linear ion trap Fourier transform ion cyclotron resonance mass spectrometer. For singly charged cluster ions (n = 1), mass spectra for CID and EID of the precursor exhibit clear differences, which become more pronounced for the larger cluster ions. Whereas CID yields fewer product ions, EID produces all possible [(NaCl)(x)Na](+) product ions. In the case of doubly charged cluster ions, EID again leads to a larger variety of product ions. In addition, doubly charged product ions have been observed due to loss of neutral NaCl unit(s). For example, EID of [(NaCl)(11)(Na)(2)](2+) leads to formation of [(NaCl)(10)(Na)(2)](2+), which appears to be the smallest doubly charged cluster of sodium chloride observed experimentally to date. The most abundant product ions in EID spectra are predominantly magic number cluster ions. Finally, [(NaCl)(m)(Na)(2)](+*) radical cations, formed via capture of low-energy electrons, fragment via the loss of [(NaCl)(n)(Na)](*) radical neutrals.