ABSTRACT:   This is a short review of previous published and unpublished results of our Cornell University group pertaining to the observations of damped nuclear spin-wave modes in spin-polarized atomic hydrogen gas.

ABSTRACT:   We have conducted preliminary spin echo experiments in spin polarized hydrogen. The heights of the echoes follow a remarkable pattern, and we often see a regular series of additional peaks in the FID envelope which resemble multiple echoes. We conjecture that molecular fields, with due regard for boundary conditions, could account for most of the observed effects.

ABSTRACT:   We report the results of continuing experiments on the spin transport properties of a dilute quantum gas, spin polarized hydrogen H↓. Spin wave resonances are prominent features of the pulsed Fourier transform NMR spectrum. For small tipping angles, the dependence of the spectrum on polarization and temperature are found to be in good qualitative agreement with theory. Preliminary results are presented on the large tipping angle spectrum, which exhibits a number of features not observed in the small angle spectrum.

ABSTRACT:   We have observed narrow, distinct resonances in the NMR spectrum of dilute spinpolarized atomic hydrogen gas (n˜10¹⁶ atoms∕cm³). The dependence of the observed spectra on temperature, density, polarization, and magnetic field gradient is consistent with theoretical predictions for spin-wave excitations damped by diffusion. We have measured the parameter μ, which is a measure of the importance of exchange effects in spin-transport processes, and the diffusion coefficient D₀, both of which are in reasonable agreement with theory.