The Proton Density of States in Confined Water (H2O)

International Journal of Molecular Sciences

Francesco Mallamace¹  Sow-Hsin Chen¹  Enza Fazio²  Domenico Mallamace²  Carmelo Corsaro² 

[1] Department of Nuclear Science and Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA;Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra (MIFT), Università di Messina, 98166 Messina, Italy;

关键词: water;    confined water;    density of states;    inelastic neutron scattering;   

DOI  :  10.3390/ijms20215373

来源: DOAJ

【 摘 要 】

The hydrogen density of states (DOS) in confined water has been probed by inelastic neutron scattering spectra in a wide range of its P−T phase diagram. The liquid−liquid transition and the dynamical crossover from the fragile (super-Arrhenius) to strong (Arrhenius) glass forming behavior have been studied, by taking into account the system polymorphism in both the liquid and amorphous solid phases. The interest is focused in the low energy region of the DOS ( $E<10$ meV) and the data are discussed in terms of the energy landscape (local minima of the potential energy) approach. In this latest research, we consider a unit scale energy (EC) linked to the water local order governed by the hydrogen bonding (HB). All the measured spectra, scaled according to such energy, evidence a universal power law behavior with different exponents ( $\gamma$ ) in the strong and fragile glass forming regions, respectively. In the first case, the DOS data obey the Debye squared-frequency law, whereas, in the second one, we obtain a value predicted in terms of the mode-coupling theory (MCT) ( $\gamma \simeq 1.6$ ).

【 授权许可】

Unknown