An Acceptor Equivalent of H the A Ion

Final state Transition energy Excited state energy (Bes,Bei) Excited state energy (boron) 

The close similarity between the B, B, A set of lines and the B[, Bi, Ai set at higher energy had led to assume that the latter one was due to an IBE, possibly due to a (Bes, J ei j pair perturbed by a nearby C atom [176]. A comparison of the PL excitation spectra and the photoinduced far-IR spectra in Be-doped silicon samples with a low and high value of [Cs] allowed to detect a new IA spectrum with an ionization energy 35 rrioV in the sample with a high [Cs] value, in addition to the above-discussed one, and this seems to confirm the above suggestion about the structure of this new IA [105]. 

Calculations of the atomic structures of the Be-related centres in silicon favour for the Be2 pair, discussed in this section, a (Bes, Bei) pair along a 111 axis [169], and this is confirmed by the experimental results of [76] on a local vibrational mode of the Be2 pair. 

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