A magnetically focused molecular beam of spin selected ortho-water

Like hydrogen molecules, water molecules also exist as two spin isomers, ortho and para- water, with the nuclear magnetic moments of the hydrogen atoms either parallel or anti-parallel. The ratio of the two spin isomers and their physical properties play an important role in a wide variety of research fields, ranging from astrophysics to nuclear magnetic resonance (NMR). Unlike hydrogen, separation of the two isomers is not readily available, and various attempts are being made to separate the two and study their different physical properties. In 2002, the first successful separation was reported, where the separation mechanism was assumed to be related to different adsorption properties of the two spin isomers, however this technique is still poorly reproducible, and its origin is not fully understood [1,2].

In a recent set of experiments, we have successfully formed a focused molecular beam of spin selected ortho-water using an alternative approach - magnetic focusing of a slow molecular beam [3]. An exciting aspect of our approach is that the magnetic selection allows us to produce a highly spin-polarized beam which can be used to deposit "magnetized overlayers". The results we obtained so far and some of the exciting surface science applications which might become possible using this spin selected beam, will be presented in the talk.

[1] V. I. Tikhonov and A. A. Volkov, Science, 296, 2363(2002).

[2] S. L. Veber. E. G. Bagryanskaya and P. L. Chapovsky, J. Exp. Theo. Phys., 102, 76(2006).

[3] T. Kravchuk, M. Reznikov, P. Tichonov, N. Avidor, Y. Meir, A. Bekkerman and G. Alexandrowicz, Science, 331, 319 (2011).