On 10/29/2011 09:34 PM, paul swed wrote:
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.
A feature shared with H, Ru and Cs, which does not exclude them from
being selected.
Cheers,
Magnus
On Sat, Oct 29, 2011 at 3:12 PM, Poul-Henning Kamp<[email protected]>wrote:
In message<[email protected]>, 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
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