IONIZATION PROBABILITY CURVES USING AN ELECTRON SELECTOR: RESULTS ON N₂⁺, N⁺, Xe⁺⁺

Abstract

An apparatus consisting of an electron energy selector built into a mass spectrometer is described. With it, initial ionization yield curves may be obtained. The interpretation of these curves is discussed, and the following new measurements reported:[Formula: see text]

Electron monochromator-mass spectrometer instrument for negative ion analysis of electronegative compounds

“…The electrostatic parallel-plate electron-energy selector (34, 35) was simple in design, but Helmholz coils were necessary to shield out stray magnetic fields. A 127" cylindrical electrostatic deflector (36)(37)(38) was one of the more popular early electron monochromator designs, because the foci of electron trajectories are located at the field boundaries. With this device, electron beams of A with energy bandwidths < 0.1 eV and energy range of 0-50 eV became available (37).…”

Grating Metal Structure with Low-K Benzocyclobutene and Electroplated Copper for High-Q Spiral Inductors

“…Evidence for this comes from the discontinuities observed in the N + ionization efficiency curve within a few volts of threshold, (Clarke 1954, Burns 1955, Frost and McDowell 1956 and Kresling 1967, Kieffer andVan Brunt 1967). The poor agreement as to the position of the discontinuities and hence the corresponding dissociation limits suggests that the situation is more complicated that any single experiment indicates.…”

“…Previous more detailed studies have suggested that breaks occur in the curve at -16.7 eV and -18.75 eV corresponding to the production of ions from the ~'l7" and B~C: states of N l . (Frost and McDowell 1955, Clarke 1954, Fox 1961, Kaneko 1961, Winters et a1 1966, Peresse et a1 1967, Hierl and Franklin 1967. There are also a number of reports ofstructure in the curve associated with autoionization (see Carbonneau and Marmet, 1973 and references therein).…”

“…Although straight line segments give a reasonable fit to the curve, it is more consistent with a smooth curve. A number of previous measurements Clarke (1954), Burns (1955), Frost and McDowell(1956), Kieffer and Van Brunt (1967), Ehrhardt and Kresling (1967), using better electron energy resolution andjor ion energy analysis, have been analysed in terms of straight line segments corresponding to different processes for the ion production. The discrepancies between some of these measurements is fairly large and again in some cases a smooth curve would appear to be a better fit to the data.…”

Calculated Calibration Points for Negative Ion Appearance Potentials

“…7 M EASUREMENTS of the appearance potentials of negative ions in the mass spectroscop~c a~~lysis of molecules are handicapped by the unavaIlabllIty of convenient and accurate standards for calibrating the effective energy of the electrons in the ion source. 7 M EASUREMENTS of the appearance potentials of negative ions in the mass spectroscop~c a~~lysis of molecules are handicapped by the unavaIlabllIty of convenient and accurate standards for calibrating the effective energy of the electrons in the ion source.…”