Int. J. Hydrogen Energy, Vol, 9~ No. 6, p. 543. 1984. Printed in Great Britain.

TECHNICAL NOTE

0360-3199/84 $3.00 + 0,00 Pergamon Press Ltd.

(~ 1984 International Association for Hydrogen Energy.

ON METALLIC HYDROGEN

VITI'ORIO NARDI

Department of Physics, University of Ferrara, Ferrara, Italy and Department of Physics, Stevens Institute of Technology, Hoboken, NJ 07030, U.S.A.

(Received for publication 18 October 1983)

The theoretical analysis indicates that metallic hydro- gen, which could store 100 times more energy as com- pared with the same mass of liquid hydrogen,* may be produced at a pressure of about one megabar or at some higher pressure from 1 to 20 megabars. Successful experiments have been claimed since 1975 [1, 2] on the basis of an observed sharp drop of the hydrogen resis- tivity at peak pressure. Some doubts can be advanced on the experimental methods [3, 4].

More recently a positive experiment has been com- pleted at the Lawrence Livermore Laboratory by R. Hawke [5, 6]. The main difficulty is usually related to the high-pressure systems with the objective of pro- ducing metallic hydrogen (e.g. Department of Materials Science and Engineering, Cornell University, Ithaca, New York, U.S.A. with A. L. Ruoff, K. S. Chan, J. Wanagel; Geophysical Laboratory, Carnegie Institution of Washington, Washington, D.C., U.S.A. , with D. Mao and P. M. Bell).

We can hope that in the near future new experiments will eliminate all doubts on the performance of the high-pressure systems and on the diagnostic methods which can verify that in fact metallic hydrogen is pro- duced (specifically spectroscopic methods for the struc-

* This order-of-magnitude estimate accounts for the heavy co-reactant (02) of the molecular liquid phase and for the large volume container of the liquid hydrogen with density 14-15 times smaller than the estimated density of the metallic (atomic) hydrogen.

ture analysis of compressed hydrogen should be coupled with resistivity measurements). After completing this essential work, and only then, we can realistically devote more of our attention to daring projects for determining how to conveniently produce, handle and exploit metallic hydrogen.

This note stems from a discussion with Professor Kurt H. Weil of Stevens Institute of Technology who pre- sented the content of this note in his talk at the closing session of the WHEC-IV in Pasadena, California, 17 June 1982. Work supported in part by ONR, Arlington, Virginia, U.S.A.

REFERENCES

1. L. F. Vereshehagin, E. N. Yakovler and Yu. A. Timofeev, JEPT Lett. 21, 85 (1975).

2. N. Kawai M. Togaya and O. Mishima, Proc. Japan Acad. 51,630 (1975).

3. A. L. Ruoff, in Proc. Int. Conf. on High-Pressure and Low-temperature Physics, Cleveland State University, Ohio, U.S.A., 20-22 July 1977 (C. W. Chu and J. A. Woollam, eds.), pp. 1-20. Plenum Press, New York (1978).

4. A. K. McMahan,. in Proc. Int. Conf. on High-Pressure and Low-Temperature Physics, Cleveland State University, Ohio, U.S.A., 20-22 July 1977 (C. W. Chu and J. A. Woollam, eds.), pp. 21--42. Plenum Press, New York (1978).

5. R. Hawke, in Proc. 2nd Int. Conf. Megaganss Physics and Technology (P. Turchi, ed.), pp. 117-130. Plenum Press, New York.

6. R. Hawke, Phys. Rev. Letts. 41,994 (1978).

543