Hyperfine Structure and Exchange Narrowing of Paramagnetic Resonance

Discussion of electronic paramagnetic resonance for the free radical a, a-diphenyl β-picryl hydrazyl as observed by its effect on the transmission of microwaves through a TE {sub 01} cavity with a small amount of the free radical placed approximately on the axis of the cavity; the half-width of this resonance at half maximum absorption was 1.45 oersteds

FURTHER ASPECTS OF THE THEORY OF THE MASER. Special Technical Report on RESEARCH INVESTIGATION DIRECTED TOWARD EXTENDING THE USEFUL RANGE OF THE ELECTROMAGNETIC SPECTRUM

The theory of the molecular transitions which are induced by the microwave field in a maser and the effects of various design parameters are examined in detail. It is shown that the theoretical minimum detectable beam intensity when the maser is used as a spectrometer for the 3-3 line of ammonia is about 10{sup 9} molecules/sec under typical experimental conditions. Various systematic frequency shifts and random fequency fluctuations of the maser oscillator are discussed and evaluated. The most prominent of the former are the"frequency-pulling" effect which arises from detuning of the cavity and the Doppler shift due to the asymmetrical coupling of the beam with the two travelling wave components of the standing waves which are set up in the cavity. These two effects may produce fractional shifts as large as one part in 10{sup 9}. If adequate precautions are taken, however, they can be reduced to one part in 10{sup 10} or possibly less. The random fluctuations are shown to be of the order of one part in 10{sup 13} under typical operating conditions. For molecular beams in which the electric-dipole transition is used the TM{sub 010} mode is usually the most suitable for the maser while in atomic beams in which magnetic transitions are utilized, the TE{sub 011} mode is to be preferred

The Effect of Electronic Paramagnetism on Nuclear Magnetic Resonance Frequencies in Metals

Observations on the shifts of nuclear resonances in metals (Id {sup 7}, Na {sup 23}, Ou {sup 63}, Be {sup 9}, Fe {sup 207}, A1 {sup 27} and Oa {sup 69}) due to free electron paramagnetism; comparison with theoretical values

Nuclear Quadrupole Moments and Nuclear Shell Structure

Describes a simple model, based on nuclear shell considerations, which leads to the proper behavior of known nuclear quadrupole moments, although predictions of the magnitudes of some quadrupole moments are seriously in error