Coulomb explosion during the early stages of the reaction of alkali metals with water

0443646 - ÚOCHB 2016 RIV GB eng J - Journal Article
Mason, Philip E. - Uhlig, Frank - Vaněk, Václav - Buttersack, T. - Bauerecker, S. - Jungwirth, Pavel
Coulomb explosion during the early stages of the reaction of alkali metals with water.
Nature Chemistry. Roč. 7, č. 3 (2015), s. 250-254. ISSN 1755-4330. E-ISSN 1755-4349
R&D Projects: GA ČR GBP208/12/G016
Institutional support: RVO:61388963
Keywords : sodium-potasium alloy * water * coulomb explosion * high-speed camera * molecular dynamics
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 27.893, year: 2015

Alkali metals can react explosively with water and it is textbook knowledge that this vigorous behaviour results from heat release, steam formation and ignition of the hydrogen gas that is produced. Here we suggest that the initial process enabling the alkali metal explosion in water is, however, of a completely different nature. High-speed camera imaging of liquid drops of a sodium/potassium alloy in water reveals submillisecond formation of metal spikes that protrude from the surface of the drop. Molecular dynamics simulations demonstrate that on immersion in water there is an almost immediate release of electrons from the metal surface. The system thus quickly reaches the Rayleigh instability limit, which leads to a 'coulomb explosion' of the alkali metal drop. Consequently, a new metal surface in contact with water is formed, which explains why the reaction does not become self-quenched by its products, but can rather lead to explosive behaviour.
Permanent Link: http://hdl.handle.net/11104/0246353