Behaviour of water containing materials in the high vacuum of an X‐ray photoelectron spectrometer

In order to examine the behaviour of water containing materials in the high vacuum of an electron spectrometer, semi‐quantitative XPS measurements of the atomic ratio of O to an element in certain inorganic compounds were carried out. Materials investigated were CuSO 4 ·5H 2 O, KCr(SO 4 ) 2 ·12H 2 O, FeC 2 O 4 ·2H 2 O, Sn(OH) 2 , Al(OH) 3 , Fe(OH) 3 , Ti(OH) 4 , Zn(OH) 2 , Zr(OH) 4 and some metals. It can be anticipated from the correlation between the vapour pressure, of water and temperature that water containing materials, which are dehydrated under 400 °C at normal pressure, lose water under a vacuum of about 10 −8 Torr. Of course, it became clear that measurements of water containing materials in the high vacuum should be performed very carefully.