Temperature dependence of the generalized frequency distribution of water molecules: comparison of experiments and molecular dynamics simulations

Abstract

International audienceThe results of inelastic neutron scattering experiments on water in the temperature interval 300–623 K along the coexistence curve are compared with data obtained from molecular dynamics simulations. In general, a good agreement between experiments and calculations is observed and it serves as a satisfactory test of the potential models employed. The temperature dependence of the generalized frequency distribution of water molecules obtained by both experiment and molecular dynamics demonstrates the accordance with the temperature evolution of the water structure, extracted from neutron and X-ray diffraction measurements

Vibrational spectra of light and heavy water with application to neutron cross section calculations

“…where σ H and σ O are, respectively, the bound-atom scattering cross sections for hydrogen and oxygen. The measurements by Novikov show a librational band that stretches up in the higher frequency region, which are not observed neither in previous experimental measurements 18 nor in other molecular dynamics calculations 9 and could be interpreted as librational overtones that survived the multiphonon correction of the spectrum. Overall, both experimental and calculated results show the same features: a peak at ∼6 meV, which is usually interpreted 19 as O-O-O bending in the hydrogen bond network, and a librational band centered at ∼60 meV.…”

“…2,3 Molecular dynamics (MD) methods offer a powerful tool to obtain microscopic information of the molecular motions of liquid water and provide a background for the interpretation of experimental data: calculations of the frequency spectra of water from MD using flexible models show good agreement with experiments. [4][5][6][7][8][9] In particular, Martí, Padro, and Guàrdia 8 did an extensive work to calculate the frequency spectra of liquid light and heavy water at different temperatures and pressures using a flexible SPC water model (SPC-MPG). More recently, Lisichkin 9 compared these results with experimental data from inelastic neutron scattering in light water.…”

“…[4][5][6][7][8][9] In particular, Martí, Padro, and Guàrdia 8 did an extensive work to calculate the frequency spectra of liquid light and heavy water at different temperatures and pressures using a flexible SPC water model (SPC-MPG). More recently, Lisichkin 9 compared these results with experimental data from inelastic neutron scattering in light water. 10 In this paper, we extend the work by Marti et al, 8 and by Lisichkin et al, 9 comparing vibrational spectra calculaa) Author to which correspondence should be addressed.…”

“…More recently, Lisichkin 9 compared these results with experimental data from inelastic neutron scattering in light water. 10 In this paper, we extend the work by Marti et al, 8 and by Lisichkin et al, 9 comparing vibrational spectra calculaa) Author to which correspondence should be addressed. Electronic mail: marquezj@cab.cnea.gov.ar.…”

Validation of Thermal Scattering Laws for Light Water at Elevated Temperatures With Diffusion Experiments

“…Likewise, experimental thermal scattering data for water at elevated ܶ is very sparse. The little data available is either for cold neutrons (< 1 meV) [12,13,14] of marginal interest in reactor applications or for limited select ܶ [15,16,17]. Not surprisingly, light-water TSL performance has been thoroughly validated at RT, but comprehensive non-proprietary validation across the full range of ܶ of interest in reactor applications is lacking.…”