Guided-ion-beam technique

Maier (longitudinal tandem mass spectrometer) and Teloy and Gerlich (guided-ion-beam technique). (The former data were taken from their published paper and may be inaccurate, since the figure therein was small and the data were plotted on a logarithmic scale.) Note that in neither case has correction been made for target motion. Ep is the laboratory energy of the neon ion. 

Figure 19 shows the acceptable agreement between the data available in 1971, and the predictions of Rapp and Francis. More recent data, obtained with the guided-ion-beam technique (Section 3.3.3) are significantly higher = 10.3 A at 1.0 eV and 8.8 A at 5.0 The new... 

Monitoring the thresholds of endothermic reactions by the guided ion-beam technique is one of the methods used to obtain the most accurate bond energies (see also Chapter 2.12). Similar measurements can be performed employing the FTICR technique. General types of endothermic reactions studied to obtain BDEs are as follows (Mt is a bare or ligated metal ion). 

Collision-induced dissociation of protonated indole with Xe has been studied as a function of kinetic energy using guided ion beam tandem mass spectrometry techniques <2007MI388>. 

More recently, Armentrout s group at the University of Utah has applied the guided ion beam (GIB) technique to determine thermochemical... 

The reactivity of the clusters can then be studied by various experimental techniques, including fast flow reactor kinetics in the postvaporization expansion region of a laser evaporation source [21, 22], ion flow tube reactor kinetics of ionic clusters [23, 24], ion cyclotron resonance [25, 26], guided-ion-beam [27], and ion-trap experiments [28-30]. Which of these techniques is applied depends on the charge state of reactants (neutral, cationic, anionic), on whether the clusters are size-selected before the reaction zone, on single or multiple collisions of the clusters with the reactants, on the pressure of a buffer gas if present, and on the temperature and collision energy of the reactant molecules. 

Using a guided ion beam instrument the translational energy dependent reaction cross sections of endothermic fragmentation processes can be determined [32]. Modelling these cross sections ultimately yields their energy thresholds and a great deal of valuable thermochemical information has been derived with this technique. Precision of 0.2 eV can be obtained for reaction thresholds. Bimolecular reactions can also be studied and reaction enthalpies derived from the analysis of the cross section data. 

The conventional type of drift-tube (DT) experiment, in which ions drift under the influence of a weak electric field, has been widely used in the measurement of ion mobilities, equilibrium constants, and IMR rate constants as a function of ion kinetic energy from 0.05 to about 5 eV [9]. The capabilities of this technique have been extended soon by incorporating an ion drift-tube section into the gas-flowing region of the basic FA device [10]. These FA and DT instruments (namely, flow-tube mass spectrometry) and their many derivative techniques such as the powerful selected ion flow tube (SIFT) method, variable temperature FA, and guided ion beam tandem mass spectrometry have been employed in many laboratories worldwide. 

A special solution for obtaining very slow ions is the so-called trapped ion beam technique, a method which has been described in Ref. 10. Using an ion guide, e.g. an octopole, together with meV potential barriers, one can store nearly monoenergetic ions at meV laboratory energies. So far this method has been used only in a few cases, e.g. for He+ stored in O2. For this system, experiments have been performed with He+ ions trapped at... 

Guided ion-beam tandem mass spectrometric techniques have been used to measure reaction threshold energies for proton transfer in the endoergic reactions... 

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