Disappearance of the Ore gap

Now let us estimate the low boundary, Wiow, of the Ore gap in molecular liquids. Because the Ore process is just an electron-transfer reaction, we assume that no rearrangement of molecules occurs and, therefore, the final positronium state will be quasi-free (formation of the bubble requires much longer time). The corresponding Born-Haber cycle is the following  

For example, in liquid water II = 8.8 eV, V w —1.2 eV. This relationship gives Wiow w 8-9 eV. It exceeds the lowest energy threshold Weoc 6.7 eV of electronic excitations, so in water, apparently, the Ore gap completely disappears. This takes place in the majority of molecular liquids, which explains the inefficiency of the Ore mechanism there. 

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