Separating para and ortho water.

@article{Horke2014SeparatingPA,
  title={Separating para and ortho water.},
  author={Daniel A. Horke and Yuan-Pin Chang and Karol Długołȩcki and Jochen K{\"u}pper},
  journal={Angewandte Chemie},
  year={2014},
  volume={53 44},
  pages={
          11965-8
        }
}
Water exists as two nuclear-spin isomers, para and ortho, determined by the overall spin of its two hydrogen nuclei. For isolated water molecules, the conversion between these isomers is forbidden and they act as different molecular species. Yet, these species are not readily separated, and no pure para sample has been produced. Accordingly, little is known about their specific physical and chemical properties, conversion mechanisms, or interactions. The production of isolated samples of both… 

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