Extraordinarily slow nuclear spin relaxation in frozen laser-polarized 129Xe

We studied the very slow nuclear spin-lattice relaxation of solid 129 Xe as a function of temperature and magnetic field using laser-polarised nuclei. Relaxation times in excess of 500 h were measured. We present evidence for a new relaxation mechanism which results from a Raman spin-phonon scattering process involving the spin-rotation interaction. We also establish the existence of cross relaxation between 129 Xe and the other magnetic isotope 129 Xe and demonstrate that laser-polarised 129 Xe can be used to cross polarise other nuclei that are present in the lattice