Positive static SIMS spectra

Figure 4.8 Positive static SIMS spectra of a MoCVSiCtySiOOO) model catalyst, after impregnation (lop) and after sulfidation in 10% H2S in H2 at the indicated temperatures, showing the transition from M0O3 to MoSj. The patterns are those of Mo+ (92-100 amu), MoO+ (108-116), MoS+ + Mo02+ (124-132) (from de Jong et al. [21J).

Figure 1 shows a positive static SIMS spectrum (obtained using a quadrupole) for polyethylene over the mass range 0—200 amu. The data are plotted as secondary ion intensity on a linear y-axis as a function of their chaige-to-mass ratios (amu). This spectrum can be compared to a similar analysis from polystyrene seen in Figure 2. One can note easily the differences in fragmentation patterns between the...

Figure 4. Positive static SIMS spectrum of cleaned PMDA-ODA (PI) film. Primary beam 4.5 keV, 60 pA Xe +. In all subsequent figures the same SIMS conditions were used.

Unfortunately, PI of the PMDA-ODA type does not generate a highly characteristic static SIMS spectrum in either the positive or negative mode. A typical spectrum of a cleaned PI surface is shown in Figure 4. Spectra of many other commercial PI films have recently been published (18). Fragment 55 is C3H30+ formed by the carbonyl groups and two C atoms of... 

Figure 3.13 Positive and negative static SIMS spectrum from a mild steel substrate coated with a y-glycidoxypropyltrimethoxysilane primer [137].

Figure 8.14 Positive ion ToF SIMS spectrum of polystyrene. (Reproduced with permission from D. Briggs, Surface Analysis of Polymer by XPS and Static SIMS, Cambridge University Press, Cambridge, UK. 1998 Cambridge University Press.)...

Figure 22 Positive spectrum from phenylalanine on a Ag foil obtained with 2.25 keV Ar+ bombardment under static SIMS conditions (from Ref. 22).

Figure 7. Static SIMS spectra of PTFE film after alkali etching, (a) positive ion spectrum, (b) negative ion spectrum.

Perform charge compensation for all samples using a pulsing electron flood (Ek = 20 eV) at a rate of one electron pulse per five ion pulses (see Note 1). Analyze surfaces in squares of 20 x 20 p,m to produce a S-SIMS spectrum. Acquire aU positive and negative spectra within 1-10 min with a fluence of less than 10 ions/cm ensuring static conditions on the sample. 

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