Confinement effect on dipole-dipole interactions in nanofluids.

Intermolecular dipole-dipole interactions were once thought to average to zero in gases and liquids as a result of rapid molecular motion that leads to sharp nuclear magnetic resonance lines. Recent papers have shown that small residual couplings survive the motional averaging if the magnetization is nonuniform or nonspherical. Here, we show that a much larger, qualitatively different intermolecular dipolar interaction remains in nanogases and nanoliquids as an effect of confinement. The dipolar coupling that characterizes such interactions is identical for all spin pairs and depends on the shape, orientation (with respect to the external magnetic field), and volume of the gas/liquid container. This nanoscale effect is useful in the determination of nanostructures and could have unique applications in the exploration of quantum space.