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A t the National Research Laboratory of Metrology CNRLMI, we are developing an optically pumped Cs frequency standard, its design and present performance are reported here.

Spreading characteristics of novel alkanoleamineterminated perfluoropolyether (PFPE) films on carbon surfaces were investigated experimentally by using a scanning microellipsometer. It was found that the mobility of the alkanoleamine-terminated PFPE films was lower than that of conventional lubricants that have the same number of OH end groups as that of the alkanoleamine-terminated lubricants. The mobility of ZDPA with a dipropylamine end group (no OH end group) has peculiar characteristics. In other words, its mobility is higher than that of Zdol when the lubricant film thickness exceeds one monolayer. However, it is lower than Zdol when the lubricant film thickness is less than one monolayer. This may be due to unique interaction between the ZDPA amine group and the carbon overcoat.