Effective ionization potential

The metallic electrode materials are characterized by their Fermi levels. The position of the Fermi level relative to the eneigetic levels of the organic layer determines the potential barrier for charge carrier injection. The workfunction of most metal electrodes relative to vacuum are tabulated [103]. However, this nominal value will usually strongly differ from the effective workfunction in the device due to interactions of the metallic- with the organic material, which can be of physical or chemical nature [104-106]. Therefore, to calculate the potential barrier height at the interface, the effective work function of the metal and the effective ionization potential and electron affinity of the organic material at the interface have to be measured [55, 107],... 

The parameter ais the ionization energy of an electron from the p,th atomic orbital located on the Ath atom and ft is the so-called resonance integral (represented here by a simple exponential). The QB and P terms of represent corrections to the effective ionization potential due to the residual charges on the different atoms. The charges are determined by... 

The exponentials of (3.103) are sometimes referred to as the effective ionization potential, 7ett ... 

Process (22a) requires a crossing between the ionic curve of the NO -Q pair and the covalent (largely repulsive) curve due to NO-Q interaction. This crossing is followed by rapid charge recombination. Quenching cross-sections may be determined from the distance R at which the crossing takes place. Similarity to alkaline atoms is suggested by Fig. 2, in which the ionization potentials of Na, K, and NO are taken as a common reference potential. Effective ionization potentials of the A, C, and D states of NO are seen to be close to those of the Na(3P) and K(4F) states. 

The arc temperature is affected by the composition of the arc column and its effective ionization potential. Alkali metals reduce the arc temperatures since they are easily ionized and thus produce an arc column that is highly conducting. As the arcing process continues, the arc temperature will increase since the composition of the arc column changes as the low-melting constituents of the sample are removed early in the arcing process by fractional distillation. 

Field ionization is a very efficient method to detect excited atoms or molecules. If the energy of the excited Rydberg level lies above the effective ionization potential IP = Ry/n every Rydberg level is ionized. Field ionization is therefore often used to detect the population of highly excited states. 

Thus the stopping power depends on the charge and velocity of the incident particle as well as on the effective ionization potential and the atomic and mass numbers of the atoms of the medium. 

Lowering the effective ionization potential enhances electron backdonation between metal and adsorbate. The authors have discussed this effect extensively elsewhere... 

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