DIELECTRONIC EXCITATION AND RECOMBINATION IN CRYSTAL CHANNELS

Dielectronic excitation and recombination has been observed during the interaction of channeled ions (H-like S, Ca and Ti, and He-like Ti) with the electrons contained in 〈110〉 and 〈100〉 channels in Si. As in dielectronic recombination, the products of the reaction are an ion of reduced charge state and the emission of a photon(s). However, the high electron density in the channel introduces collisional mechanisms for the destruction of the doubly excited intermediate state and even the formation of ions with increased charge state. The experiments prove that crystal channels may be treated quantitatively as a dense electron target for ions with velocity νi ≫ νF, the Fermi velocity of the electrons in the channel. © 1990.