Title: Ice $I_h$ revisited: No proton tunneling observed in a quasielastic neutron scattering experiment

Abstract

A large broadening ($${\sim}0.4\mathrm{meV}$$) of quasielastic neutron scattering (QENS) signal in $${\mathrm{H}}_{2}\mathrm{O}$$ ice $${I}_{h}$$ at $$T=5\mathrm{K}$$ was observed by Bove et al. [Phys. Rev. Lett. 103, 165901 (2009)] and explained by a model of concerted proton tunneling. This result was rather unexpected, as prior studies never showed significant mobility in water at low temperatures and ambient pressure. There were a few attempts of theoretical understanding of the effect. Recent path-integral simulations as well as quantum lattice-gauge theory supported the possibility of the collective tunneling of protons in ice $${I}_{h}$$, however other studies stated that concerted tunneling in ice $${I}_{h}$$ should have very low frequency. In this paper, we report on QENS measurements of $${\mathrm{H}}_{2}\mathrm{O}$$ ice $${I}_{h}$$ at 1.8 and 5 K by using neutron scattering spectrometers with the energy resolution similar to and four times better than the energy resolution in the original experiment of Bove and co-workers. We did not observe any QENS broadening, and the measured spectra for the ice $${I}_{h}$$ and the reference vanadium sample were almost identical. Therefore, we conclude that there is no proton tunneling in ice $${I}_{h}$$ at temperatures down to 1.8 K measurable on an energy scale of 3.5 $${\mu}\mathrm{eV}$$ and above. Finally, the literature data on low-temperature heat capacity of ice $${I}_{h}$$ support this conclusion.

Authors:

Kolesnikov, Alexander I. ^[1]; Ehlers, Georg ^[2]; Mamontov, Eugene ^[1]; Podlesnyak, Andrey ^[1]

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+ Show Author Affiliations

1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Neutron Scattering Division
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Neutron Technologies Division

Publication Date:

Tue Aug 07 00:00:00 EDT 2018

Research Org.:

Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1463998

Alternate Identifier(s):

OSTI ID: 1463212

Grant/Contract Number:  

AC05-00OR22725

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review B

Additional Journal Information:

Journal Volume: 98; Journal Issue: 6; Journal ID: ISSN 2469-9950

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; quasi-elastic neutron scattering