Ammonia was the first clock wasn't it? Potentially Na and K have reactive behaviors like catching on fire that isn't attractive to a manufacturing process.
On Sat, Oct 29, 2011 at 3:12 PM, Poul-Henning Kamp <p...@phk.freebsd.dk>wrote: > In message <20111029201927.b7a1130c.att...@kinali.ch>, Attila Kinali > writes: > > >Is it because they can be aproximated as single electron > >systems due to the one electron in the valence orbit? > > Yes. Basically that electron is in a "figure of eight" orbital > which means that it passes straight through, or possibly just > very close by, the proton, allowing their spin moments to interact. > > >Related to this is the question why only H, Rb and Cs are used. > >Although, from my point of view there isnt anything that speaks > >against using Li, K or Na, these are not used at all. At least i > >couldnt find any papers or other documents describing frequency > >standards build on these elements. > > I belive K has been tried. > > I belive the preference for H, Rb & Cs is that getting them as > single atoms doesn't require high temperatures. > > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > p...@freebsd.org | TCP/IP since RFC 956 > FreeBSD committer | BSD since 4.3-tahoe > Never attribute to malice what can adequately be explained by incompetence. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.