Flight times ionic

It is found that with this calibration method ionic masses can be derived with an accuracy of 0.01 to 0.05 u for light to heavy elements. With a proper calibration, the shape of the mass lines also appears much more symmetric and a better mass resolution is achieved. But again, the system cannot be used for an ion energy analysis because of the flight-time-focusing scheme. 

The incident ions cause recoil in the surface atoms. In studies of ionic liquids, only direct recoil - that is, motion in the forward direction - was measured. Watson and co-workers [56, 57] used time-of-flight analysis with a pulsed ion beam to measure the kinetic energies of the scattered and sputtered ions and therefore determine the masses of the recoiled surface atoms. By relating the measured intensities of the... 

Carda-Broch, S., Berthod, A. and Armstrong, D. W., Ionic matrices for matrix-assisted laser desorption/ionization time-of-flight detection of DNA oligomers. Rapid Commun. Mass Spec., 17, 553, 2003. 

Ionic evaporation can be evidenced by studying carefully the shape of the mass peaks in time-of-flight mass spectroscopic measurements. The simple method used here to identify evaporation has already been demonstrated [28-31]. It is based on the detection of the translational energy if an evaporation occurs, some kinetic energy is released and its evaluation allows one to distinguish between non-evaporating clusters and those that have undergone evaporation. 

The diffusion coefficients of the ions can be determined through time-of-flight techniques. For a liquid crystalline material between two ITO coated plates with an initial voltage V, a sudden increase in the voltage to Vi allows the ionic mean transit time t j and the ion mobility to be determined by the relations [69] ... 

Intense EE and PIE have been observed during fracture as well. In recent work, we have succeeded in determining the predominate ionic species created during the fracture of UV grade fused silica. (Langford, S. C. Dickinson, J. T. Jensen, L. C. J. Vac. Sci. Technol. A. in press.). Both time-of-flight and quadrupole mass spectroscopy indicate the presence of ions of mass 16,28,44, and 76, which we... 

Mass spectrometers (MSs) are classified by the technology they use to separate ionic masses into clusters. Their examples include the quadrupole, magnetic sector, time-of-flight, and ion-trap mass spectrometers. 

Dendrimer characterization was accomplished by 13C, NMR and FT-IR spectroscopy as well as mass spectrometry using fast atom bombardment (FAB) and matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) techniques. Molecular ion base peaks were observed in the MALDI-TOF MS of polyester 168 (mlz 18900 (calcd. 19044)) along with minor peaks at 37000 and 54000 mlz corresponding to ionic gasphase dimer and trimer complexes. 

Figure 13.6 Schematic setup of Assion et al. experiment [43], Femtosecond laser pulses are modified in a computer-controlled pulse shaper. Ionic fragments from molecular photodissofy ciation are recorded with a reflection time of flight mass spectrometer. This signal is used directly as feedback in the controlling evolutionary computer algorithm to optimize branching ratios of photochemical reactions. (Taken from Fig. 1, Ref. [43].)...

Obtaining the individual properties of ions with solvation numbers from measurements of ionic vibration potentials and partial molar volumes is not necessary in the study of gas phase solvation (Section 2.13), where the individual heats of certain hydrated entities can be obtained from mass spectroscopy measurements. One injects a spray of the solution under study into a mass spectrometer and investigates the time of flight, thus leading to a determination of the total mass of individual ions and adherent water molecules. 

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