Quantum thermodynamics of hydrogen in nano-structured materials—H2 in carbon nanotubes

Abstract

Abstract Modern quantum theory of correlations predicts, and reveals, new counter-intuitive dynamical effects of hydrogen in nano-structured materials, being of considerable importance for basic research as well as for technological applications. To support this claim, here the focus is on H2 molecules in carbon nanotubes and other nanocavities, as experimentally investigated with the well established technique of incoherent inelastic neutron scattering (INS). In particular, the experimentally determined momentum and energy transfers from an H2 molecule in a carbon (C-) nanotube resulting in roto-translational motion along the nanotube axis, appear to (1) either violate the standard conservations laws, or (2) attribute the translating H2 molecule a highly reduced inertia, as quantified by the effective mass M eff ≈ 0.64 a.m.u. (atomic mass units), instead of 2 a.m.u. for an isolated molecule. This counter-intuitive INS-observation has no conventional interpretation, but it can be qualitatively interpreted “from first principles” in the frame of modern theories of quantumness of correlations and Quantum Thermodynamics (QTD). This analysis also provides a surprising new physical insight: The nano-structured cavities do represent quantum systems which contribute to the quantum dynamics of the hydrogen translational dynamics, and thus to the hydrogen transport in the studied materials. This insight may also have far-reaching consequences for technological applications and material sciences (e.g. fuel cells, H storage materials, etc.), since it concerns the choice and design of “optimized” materials adsorbing or carrying hydrogen.