Oxygen as a Site Specific Probe of the Structure of Water and Oxide Materials

Abstract

The method of oxygen isotope substitution in neutron diffraction is introduced as a site specific structural probe. It is employed to measure the structure of light versus heavy water, thus circumventing the assumption of isomorphism between H and D as used in more traditional neutron diffraction methods. The intramolecular and intermolecular O-H and O-D pair correlations are in excellent agreement with path integral molecular dynamics simulations, both techniques showing a difference of ≃0.5% between the O-H and O-D intramolecular bond distances. The results support the validity of a competing quantum effects model for water in which its structural and dynamical properties are governed by an offset between intramolecular and intermolecular quantum contributions.

Zeidleret al.Reply:

“…Closer inspection shows, however, an underlying dephasing in the high Q range which manifests itself in real space. For example, the intramolecular peak in the first-difference functions ÁG D ðrÞ and ÁG H ðrÞ gives O-D and O-H bond distances of r OD ¼ 0:985ð5Þ # A and r OH ¼ 0:990ð5Þ # A from our work [1] while ''EPSR fits'' to the measured time-of-flight neutron diffraction data sets at large Q [5] lead to values of r OD ' 0:971 # A and r OH ' 1:005 # A, corresponding to bond length differences of ' 0:5% and 3%, respectively. The bond length difference that we find is comparable to the value of ' 0:4% found for both ice-Ih [9] and the vapor phase of water [10].…”

“…Zeidler et al Reply: In our Letter the method of neutron diffraction with oxygen isotope substitution was introduced to measure the structure of light (H 2 O) versus heavy (D 2 O) water, thus minimizing inelastic scattering effects [1]. Independently, path integral molecular dynamics (PIMD) simulations were made by using various models of water.…”

“…Soper and Benmore [4] object to a remark we make in Ref. [1] on their use of the Empirical Potential Structure Refinement (EPSR) method to model the diffraction data for water shown in Ref. [5] where information is reported on both the intramolecular and intermolecular correlations.…”

Development of express-evaluation method of water biological properties

“…У роботі [4] групою фізиків запропоновано та до-сліджено модель «конкуруючих квантових ефектів». Конкуруючі квантові ефекти досліджено на основі вивчення двох різних форм ізотопів водню: а) водню з одним протоном; б) дейтерію.…”

“…В Україні фе-росиліцій виробляють електротермічним способом у дугових печах змінного струму, в основному, на ПуАТ «Стахановський завод феросплавів» (Україна) [3], а також методом електрошлакового переплаву (ЕШП) у печах постійного струму на Стахановській виробничій дільниці товариства із обмеженою відповідальністю фірма «Екологічна ініціатива» (СВД ТОВ фірма «ЕКІ-НА», м. Алмазна, Луганська область) [4].…”