Studies of the atom-dimer polarization transfer

The polarization transfer between optically pumped alkali atoms and alkali molecules is studied, using the model introduced in a previous paper (Z. Physik A273, 9(1975)). It is shown that the atom-molecule-exchange reactionX+X ₂→X ₂+X is responsible for the nulear spin polarization observed in the alkali molecules, and that the recombination of the alkali atoms does not contribute to this polarization transfer.     

Chromium and chromium-boron pairs in silicon

Four different measurement techniques: EPR, NAA, DLTS, and luminescence were applied to characterize the properties of chromium in silicon. The solubility of chromium in silicon was determined and its pairing reaction with boron was studied. The energy level atE _c?0.23 eV was attributed to interstitial chromium and a second level atE _v+0.27 eV was correlated to chromium-boron pairs. The luminescence band of the chromium-boron pairs was clearly identified. The properties of chromium are compared with those of other transition metal impurities in silicon crystals.