Energy distribution of ions

Mass analysis of the negative-ion beam with a resolution sufficient to separate isotopes of heavy elements is needed prior to acceleration. For example, an electrostatic analyzer is used at the University of Toronto to sharpen the energy distribution of ions produced from a caesium sputter ion source. A pre-acceleration of the negative ion beam... 

C. Collette, E. de Pauw, Calibration of the internal energy distribution of ions produced by ESI, Rapid Commun. Mass Spectrom., 12 (1998) 165. 

Figure 3.2. Internal energy distribution of ions generated by electron ionization.

Species transport in the sheath, and the resulting angular and energy distribution of ions, electrons, and any hot neutrals bombarding the surface. 

The translational energy distribution of ions leaving a source arises from the Boltzmann distribution of cn-ergicsof the molecules from which the Ions are formed and from field inhonioiieneities in the source. The... 

Rate constants measured for the reactions in 1,3-butadiene are given in Table I and compared with those measured by Barber et for reactant ions produced by electron impact. It is seen that the agreement between the two sets of rate constants is only fair, even if a correction factor is applied so that both quantities are made equal for one reaction. If the discrepancy is outside experimental error, it may have a very interesting origin. It should be remembered that the internal-energy distribution of the reactant ions produced by photoionization extends only to 10.19 eV - /, whereas the internal-energy distribution of ions produced by electron impact can extend up to the dissociation limit of the reactant... 

The mass resolving power of TOF-MS critically relies on the energy spread of ions with the same m/z. Energy spread is dictated by spatial and energy distributions of ions at the... 

Van Straaten, M., Bogaerts, A., Gijbels, R. (1995) Experimental determination of the energy distribution of ions bombarding the cathode surface in a glow discharge. Spectrochim. Acta B, 50(4-1), 583-605. 

Note The spread in ion kinetic energies from thermal energy as well as from inhomogeneous acceleration presents a general problem in the construction of mass analyzers. Accordingly, there are numerous approaches to narrow down the kinetic energy distributions of ions or to compensate for their effects. 

There are many other reported applications of GAs in related fields. Some, which may be of interest, include finding low-energy distributions of ions above a crystal surface optimizing parameters for allosteric regulation of enzymes in a model metabolic cycle minimizing the discrepancies between experimental and theoretical fluorescence/absorption spectra thin film analysis and parameter estimation for kenetic models. ... 

Collette, C. De Pauw, E. CaUbration of the internal energy distribution of ions produced by electrospray. Rapid Common. Mass Spectrom 1998, 12, 165-170. 

---