Positronium in MOFs: the Atom out of the box
Abstract
Recently, evidence for positronium (Ps) in a Bloch state in self-assembled metal--organic frameworks (MOFs) has been reported [Dutta et al., Phys. Rev. Lett. 110, 197403 (2013)]. In this paper, we study Ps emission into vacuum from four different MOFs crystals: MOF-5, IRMOF-8, FMA and IRMOF-20. Our measurements of Ps yield and emission energy into vacuum provide definitive evidence of Ps delocalization. We determine with a different technique Ps diffusion lengths in agreement with the recently published results. Furthermore, we measure that a fraction of the Ps is emitted into vacuum with a distinctly smaller energy than what one would expect for Ps localized in the MOFs' cells. We show that a calculation assuming Ps delocalized in a Kronig--Penney potential reproduces the measured Ps emission energy.
Keywords
Cite
@article{arxiv.1309.6497,
title = {Positronium in MOFs: the Atom out of the box},
author = {P. Crivelli and D. Cooke and B. Barbiellini and B. L. Brown and J. I. Feldblyum and P. Guo and D. W. Gidley and L. Gerchow and A. J. Matzger},
journal= {arXiv preprint arXiv:1309.6497},
year = {2014}
}
Comments
5 pages, 4 figures, 4 tables, v2: added detectors resolution, some text and some acknowledgements