Auger electron spectroscopy and mass spectrometry have been used to investigate the elemental composition of single-crystalline LiNbO 3 surfaces subjected to annealing and evaporation in vacuum and to analyse the evaporation products. We found three distinct temperature regimes, within which the surface composition of LiNbO 3 undergoes different changes: outgassing (T = 300-650 K); surface segregation of Li and O (T = 650-1150 K); and evaporation of Li, O 2 and LiO (T 1150 K). The evaporation of Nb becomes noticeable only at temperatures close to the Curie temperature (1483 K).

Applying a strong electric field to a discontinuous metal film some electron and photon emission from discrete film centres (1) is observed parallel to the conduction current.The radiation mechanism of the film i s yet not clear. For clearing it up we decided to make a series of additional investigations to gather experimental data which might be generalized by a theoretical model. On the basis of the facts that the centres of electron emission and light coincide(2) and that the electron emission and radiation a r e starting at the same fields one may assume a tight connection between these effects. But as the electron emission due to electron gas heating (3) is defined by the power input into the film it proved firstly adviseable to study the dependence of the radiation characteristics upon the power input. This investigation i s just described in the present article.We used the standard technique of experimental lamp production (1). The spectral studies were performed by the photoelectric radiation registration method in the arrangement described in (4). Photomultipliers working in the regime of photon counting were used as photon detectors. Thus it was possible to study the characteristics of an individual centre and the total radiation of the whole film.The spectral resolution of the arrangement used was a s good a s 60 A . The accumulation time of the photon number within the wavelengths investigated could be changed from 1 to 100 s. The arrangement allowed to measure simultaneously the number of photons within a small spectral interval in one channel and the intensity of the unresolved light beam in another channel from the same source. 0

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