Guided ion beam mass spectrometer

Another instrument used in physical chemistry research that employs quadnipole mass filters is the guided ion beam mass spectrometer [31]. A schematic diagram of an example of this type of instrument is shown in figure B 1.7.13. A... 

In Table 5 are also shown the 0 K stepwise Ag+—CO bond dissociation enthalpies of Ag(CO)4+ from Armentrout and his coworkers49. From their collision-induced dissociation experiments in a guided ion beam mass spectrometer, one finds a nonmonotonic change in ZJo[Ag(CO)n+—CO] as a function of n. That the dissociation energy increases from n = 0 to n = I has been explained in terms of 4s-3d[Pg.62]

In Table 5 are also shown the 0 K stepwise Ag+—CO bond dissociation enthalpies of Ag(CO)4+ from Armentrout and his coworkers . From their colhsion-induced dissociation experiments in a guided ion beam mass spectrometer, one finds a nonmonotonic change in Do[Ag(CO) CO] as a function of n. That the dissociation energy increases from n = 0 to n = 1 has been explained in terms of 4s-3da hybridization Z)o[Ag+—CO] is small because it is reduced by the energy needed to hybridize the metal ion, but Do[Ag(CO) "—CO] assumes a more conventional value because the Ag(CO)+ fragment aheady has the metal in the required hybridization. In turn, Z)o[Ag(CO)+—CO] > Do[Ag(CO)2 —CO] because the third carbonyl Mgand imphes loss of the 4s-3da hybridization. FinaUy, Do[Ag(CO)2+-CO] > Do[Ag(CO)3+-CO] is explained by an increase of hgand repulsion. 

Co, Rh and Ir - Ultrafast photochemistry of [CpCo(CO)2] in 1-hexene solution followed by multichannel infrared spectra allowed the identification of the transient species [CpCo(CO)(l-hexene)]. The formation of gaseous [CoC3Hg]+ by reaction of gaseous Co+ ions with propene and subsequent decompostion pathways of the product have been followed by means of a guided-ion-beam mass spectrometer . 

Moision, R.M. and Armentrout, P.B. (2007) An electrospray ionization source for thermochemical investigation with the guided ion beam mass spectrometer. J. Am. Soc. Mass Spectrom., 18, 1124-1134. 

In essence, a guided-ion beam is a double mass spectrometer. Figure A3.5.9 shows a schematic diagram of a griided-ion beam apparatus [104]. Ions are created and extracted from an ion source. Many types of source have been used and the choice depends upon the application. Combining a flow tube such as that described in this chapter has proven to be versatile and it ensures the ions are thennalized [105]. After extraction, the ions are mass selected. Many types of mass spectrometer can be used a Wien ExB filter is shown. The ions are then injected into an octopole ion trap. The octopole consists of eight parallel rods arranged on a circle. An RF... 

GIBMS Guided ion beam tandem mass spectrometer... 

In a guided ion beam experiment, reactant ions are created in the source region, mass selected by a mass spectrometer (a magnetic sector in our instruments), decelerated to a desired kinetic energy, and injected into a radiofrequency (rf) octopole ion beam guide [10,11]. This device comprises eight rods cylindrically surrounding the ion beam path. Opposite phases of an rf potential... 

Fig. 3. Schematic diagram of the guided ion beam tandem mass spectrometer, double octopole configuration. Pumping speeds are shown. Ion sources available are listed and the microwave discharge source is shown. Adapted from [9]...

The experiments described here were performed on a guided ion beam tandem mass spectrometer [18] that was temporarily installed at the free electron laser facility FELIX (free electron laser for infrared experiments, FOM Institute for Plasma Physics, Nieuwegein, The Netherlands) [19]. A schematic of the experimental setup is shown in Fig. 3.2. Ions are generated in the ion source region (not... 

Figure 3.2 Schematic of the guided-ion-beam tandem mass spectrometer used in the present studies [60], The instrument is housed in...

Argon or helium at a pressure of 100 Torr is bubbled through JP-10, generating a reactant flow that is 5% JP-10. The reactant mix is metered into the flow-tube through a leak valve where the pressure drops to a few tori-celli. The flow properties of the reactor have been discussed in detail previously. Briefly, the total pressure in the heated zone of the flow-tube varies from 3 to 1.2 Torr over the temperature range from 300 to 1700 K, while the residence time drops from 4.5 to 1.5 ms. The flow-tube exhaust is dumped into a temperature-stabilized ( 200 °C) ionization source where the pressure is 1 Torr. The analyte molecules can be ionized either by EI or by methane Cl. The ions are then mass analyzed by the tandem guided ion-beam quadrupole mass spectrometer described in the above-referenced publications. 

The Apparatus. Experimental methods used in our laboratory to measure gas phase bond dissociation energies have been detailed before (4,5,6,7), and involve the use of a "guided" ion beam tandem mass spectrometer. Ion beam instruments are two mass spectrometers... 

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. 

TCID experiments employ tandem mass spectrometers of various types. Guided ion beam (GIB) instruments use a radio frequency octopole in the interaction region for high-efficiency collection of scattered products and low-energy ions. These instruments typically use a magnetic sector or Wien filter for initial mass analysis and... 

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