Rare-nuclei localization in solids by Hartmann–Hahn cross-relaxation

We present a special solid state NMR imaging approach which is able to give maps of the heteronuclear dipolar interaction (in this case 1H–13C) and, therefore, of the rare-nuclei distribution. Such an approach utilizes the cross-relaxation mechanism based on the Hartmann–Hahn matching condition. The cross-relaxation map is also able to provide mobile–rigid structure distribution as well as the spatial-dependent degree of cross-linking in solid polymers and elastomers.