Redetermination of the Hyperfine Splitting in the Ground State of Atomic Hydrogen

Abstract

A redetermination has been made of the zero-field hyperfine splitting of the ground state of atomic hydrogen. A microwave absorption technique was used employing a resonance line with a width of about 3 kc/sec. This width (occasionally as narrow as TV of the normal Doppler breadth) was obtained through the mechanism of collision reduction of the Doppler effect. The primary relaxation mechanism was electron exchange between hydrogen atoms. The measured result for the hyperfine splitting is Av= 1420.40580 ±0.00006 Mc/sec.

DICKE’S SUPERRADIANCE IN ASTROPHYSICS. II. THE OH 1612 MHz LINE

“…This is because during an elastic collision the spacings between energy levels for the colliding counterparts change as a result of short-range interaction forces. After a number of such collisions, each acting like a random perturbation, the molecule can lose coherence with the interacting radiation field (Wittke & Dicke 1956). Elastic collisions are normally more frequent than inelastic collisions, and the mean time between elastic collisions usually sets the timescale of collisional dephasing/relaxation T c and the corresponding condition t < T D c is required to allow the build-up of coherent interactions.…”

Microwave Atomic Oscillator Using the Hyperfine Transition of Rb87

“…and is seen to give just the negative of the above values. It seems remarkable that only the differences in initial populations between the states (1,-i) and (1,1) and between the states (2,-2) and (2,2) contribute to the final result.…”

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“…An oscillogram of a transient is shown in Figure 10 (c). g(r) = e A, T (2) and a convenient criterion is set by placing …”

Dicke narrowing in strong fields: The atom-as-antenna analogy

“…This conclusion suggests that the problem of collision-narrowing can be separated into two distinct parts: (a) As a result of the oscillator's motion, the stochas-1.. C. Camparo and R. P. Frueholtz, unpublished. 2 Experiments are now in progress at The Aerospace Corporation and Duke University to test the validity of this hypothesis. tically varying Doppler shifts (i.e., discrete frequency jumps) give rise to a nonmonochromatic electromagnetic-field power spectral density in the oscillator's rest frame.…”