Spontaneous Dipole Alignment in Films of N₂O

Experimental data obtained using low energy electron beams are presented which show that films of N₂O, of several hundred monolayers (ML), spontaneously acquire a positive potential of as high as 5 V. Films do not possess a dipole double layer but for >40  ML display a constant electric field within the material. This new phenomenon is attributed to dipole alignment. The phenomenon also shows a strong temperature dependence. This is revealed by the differing dependence of the surface potential on the film thickness at different temperatures and by electron transmission spectra which display marked structure at 62 K which is absent at 40 K.