Stability of Metallic Hydrogen at Ambient Conditions

TL;DR

This paper examines the stability of metallic hydrogen at ambient conditions, showing through density functional theory and molecular dynamics that it is highly unstable and unlikely to be recovered for practical use.

Contribution

It provides a detailed computational analysis demonstrating the instability of metallic hydrogen structures at ambient conditions, challenging previous optimistic claims.

Findings

Metallic hydrogen is highly unstable at ambient conditions.

Lifetime of metallic hydrogen structures is less than a picosecond.

Prospects for using recovered metallic hydrogen as fuel are overstated.

Abstract

The possibility of metallic hydrogen was first mooted by Wigner and Huntington in 1935. Here it is show that the calculations from that paper are in remarkably good agreement with modern density functional theory results. The possibility that metallic hydrogen could be recovered to ambient pressure is often attributed to papers by Brovman, although in fact they only say it would be metastable with undetermined lifetime. Density functional theory calculations presented here show that reasonable candidate structures for metallic hydrogen are wildly unstable at ambient conditions, and molecular dynamics calculations show that the lifetime to which Brovman et al refer is considerably less than a picosecond. It is concluded that the prospects of using recovered metallic hydrogen as rocket fuel or for electricity distribution may have been overstated.