The atomichron ® - An atomic frequency standard: Physical foundations

The periodic motions of the particles within atomic and molecular systems have long been recognized as attractive possibilities for ultra-stable oscillators and precise timekeepers. The electromagnetic fields arising from the motions of charges provide the means for observing them. Hence, practical applications of atomic and molecular resonances have involved those classes of motions which have frequencies accessible to the technique of radio fields. Several possibilities have been under study during the past few years, and this afternoon I wi 11 describe one of these which is capable of great precision and which has been reduced to routine engineering practice.