Recombination energy spectroscopic

Table II. Spectroscopic Recombination Energies RE and Effective Recombination Energies RE of Doubly Charged Positive Ions (in eV) ...

If no transfer of translational energy occurs, then the charge exchange process probably takes place when the distance between the ion and the molecule is large. This means, however, that the ion and the molecule can be considered as isolated from each other, and therefore, the recombination process of the ion and the ionization process of the molecule must obey the spectroscopic transition laws. On the other hand, if a large transfer of translational energy takes place, then the process probably takes place when the distance is small, and possibly then all selection rules break down. 

D3) absorption and emission lines (from n = 3 states) in H2 (D2) plasmas were strongly Doppler-broadened which seems to indicate high, nonthermal energies (about 0.3 eV) of the absorbing or emitting H3 molecules. The energy is close to that expected if the excited (n = 3) H3 molecules were formed by recombination of Hj, but in Amano s work no Hj ions should have been present. Perhaps, the fast H3 molecules are produced from H + H2 collisions, and the spectroscopic observations provide indirect evidence for the existence of H3 molecules. The conjecture needs to be examined by more detailed work. 

Ishizumi and Kanemitsu (2005) have studied PL properties of Eu3+ doped ZnO nanorods fabricated by a microemulsion method. The PL of bound exciton recombination and ZnO defects was observed near 370 and 650 nm under 325-nm light excitation, but no emission of Eu3+ occurred. On the other hand, the sharp PL peaks due to the intra-4f transitions of Eu3+ ions appeared under nonresonant excitation below the band-gap energy of ZnO (454 and 457.9 nm) in addition to direct excitation to 5D2 (465.8 nm). Therefore the authors concluded that the energy transfer occurs from the ZnO nanorods to Eu3+ ions through ZnO-defect states. This energy transfer mechanism seems very different from the previous one and more spectroscopic evidence is required to confirm it. 

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