Recombining energy

If the recombination leaves the atom in a high atomic state, the recombination energy will be so low that charge exchange cannot take place. Such recombination energies are not included in Table II. 

In Table II the state of the ion and the recombination energies in electron volts (computed from (65)) are given. Some very uncertain information is included in the right hand column as to the relative abundances of the metastable states of the ions when produced by electron impact with 100-e.v. electrons from the indicated compounds. 

The eventual fate of any ion is its neutralization, either by a free electron or by a negative ion formed by electron attachment. In ethylene radiolysis at high dose rates, electron capture processes should be insignificant (29), and the recombination energy of the positive ion will become available on neutralization, a portion of which may be in the form of excitation (59). 

Bassi et al. [70] have described IMR-MS for online gas analysis with a sensitivity of 100ppb-l ppm. A mass-selected ion source allows the use of three different primary ion beams (Xe+, Kr+ and CF3I+), covering the recombination energy range from 10.23 to 14.67 eV. For fast measurements, the change from one primary ion to another can be achieved by a Wien filter. IMR-MS allows quantitative analysis. 

Alternatively the necessary energy can be supplied by the impact of electrons accelerated through the appropriate potential difference (2) or more subtly by collision with another positive (often atomic) ion with a higher recombination energy (the reverse of its ionization) (3). 

Figures 2.13(a) and 2.13(b) illustrate the basis of a semiconductor diode laser. The laser action is produced by electronic transitions between the conduction and the valence bands at the p-n junction of a diode. When an electric current is sent in the forward direction through a p-n semiconductor diode, the electrons and holes can recombine within the p-n junction and may emit the recombination energy as electromagnetic radiation. Above a certain threshold current, the radiation field in the junction becomes sufficiently intense to make the stimulated emission rate exceed the spontaneous processes.

To evaluate the energy of the Schottky process, based on the energies of table 4.2, the concomitant process of anion vacancy formation and the recombination energies of cation and anion on the surface of the crystal must be added to process 4.77.)... 

Figure 2 Bolometric light curve of SN 1987 A for the assumed parameters of Sk —69 202. The dots indicate the total luminosity, the full line the luminosity due to the shock energy, the dashed line the luminosity coming from the decay of 56Ni and the dash-dotted line the recombination energy.

The ion QH was obtained by charge transfer with ions having recombination energies in... 

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