Vacancy production

When Y3+ cations are used to substitute Zr4 at the corresponding lattice sites, they also create vacancies in the oxygen sublattice since Y3+ cations have a lower valence than Zr4+. The vacancy production can be shown in Kroger-Vink notation similar to Equation 1.1. 

Equation (9.17) balances the vacancy production and the amount of reduced,... 

Fig. 9 Vacancy production probability for Pb on Ni solid targets. The triangles are the experimental values from Ref. 17.

U. Wille and R. Hippier, Mechanisms of inner-shell vacancy production in slow ion-atom collisions, Phys. Rep. 132 129 (1986). 

Itmer-Shell Vacancy Production in Ion-Atom Collisions, C. D. Lin and Patrick Richard Atomic Processes in the Sun, P L. Dufton and A. E. Kingston... 

X-rays and electronic transitions. The generation of characteristic X-rays is ascribed to the production of an original electron vacancy in the inner electron shell, followed by filling of the vacancy with an outer electron. Multiple vacancy production and subsequent appearance of satellite lines are not included in the table, but they are treated later. 

Al-Shahery et al. (1983) pointed out that between x = 0.2 and x = 0.8 carbon is accommodated via a nonstoichiometric phase at the order-disorder boundary and that the excess metal arising from vacancy production combines with carbon during cooling to form the carbides. The experimental facts have proved this hypothesis for the compound systems of the more volatile Er and Ho the R15C19 phase is precipitated when X > 0.4, and for the compounds of the less volatile Gd and Y this phase occurs at X = 0.5 and 0.7, respectively. In particular, Gd jCig has not been reported before but the X-ray pattern obtained is very similar to that from Eri 5 19 (Bauer 1974). 

Gy is the vacancy production rate from irradiation (vacancies/s)... 

Wavelength dispersive X-ray spectroscopy (WDS) may extend the threshold of detection by at least an order of magnitude as compared to the energy dispersive X-ray spectroscopy. Since the L X-ray spectra produced by heavier ions displays more complicated structure due to multiple vacancy production (Kageyama et al. 1996), WDS is must for analysis of such complex spectra. However, WDS requires optically flat, stable specimens and is limited to bulk analysis modes, limiting spatial resolution to more than 0.5 o.m. 

For ZijZi > 0.3 and for projectiles having either one vacancy or bare-projectiles, the electron capture contribution to the inner-shell target vacancy production rates become significant and must be added to direct ionization contribution. 

In Figure 29, significant discrepancies between the SHM calculations and experiment are still observed. These discrepancies are partially understood. The transition probability in the LK systems is relatively small in the range of small incident velocities, so that, there, mechanisms other than vacancy sharing become important. Unilateral screening effects due to double vacancy production in the 4a- MO and/or two-electron transitions filling the double hole states are expected to be important. 

Figure 34. Cross sections for Ar L excitation in the collision systems Si -t- Ar and S + Ar as a function of the projectile energy. The experimental data are from Schneider el The curve labeled ROT refers to 6-2v-A

Fig. 3.17. The experimental setup of Ebel et al. [3.17], used for measurements of K-vacancy production by eqwvelodty positrons and electrons. 1 lead collimators 2 target Imider 3 flange with X-ray window 4 Si(Li) detector S CBM detector. (From Ebel et aL [3.51].)...

As for He, for both Ne and Ar, the factorization into mass and charge effect of as given by eq. (6.8), describes the behavior of the e" data rather well, and even reproduces the dip -feature of the Ar data near 1 MeV/amu. This dip, which is also seen in the proton data, but which is enhanced for e, is most likely also due to the contribution from L-shell, vacancy-production-induced double ionization which grows from 20% at 0.5 MeV/amu to more than 50% at 2 MeV/amu in the case of proton impact (Andersen et al. [3.41]). 

Zee and Wilkes (1980) applied their model to data that had been obtained by various investigators on fast-and thermal-neutron irradiations of CU3AU, and claimed that there was reasonably good agreement between their model and the experimental results, particularly for irradiation times beyond the initial transient stage. The parameters used in fitting the theoretical model to the experimental data were , = 0.8eV for vacancy motion, for ordering vacancy jumps, e = 80 for fast neutrons and 20 for thermal neutrons, and a survival rate for vacancy production of 5% for fast neutrons and 100% for thermal neutrons. 

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