TY - JOUR
T1 - Indication of tunneling state of hydrogen atom in hydrogen-bonded material 5-bromo-9-hydroxyphenalenon studied by X-ray and neutron diffractions
AU - Kiyanagi, Ryoji
AU - Kimura, Hiroyuki
AU - Watanabe, Masashi
AU - Noda, Yukio
AU - Mochida, Tomoyuki
AU - Sugawara, Tadashi
N1 - Copyright:
Copyright 2011 Elsevier B.V., All rights reserved.
PY - 2008/6
Y1 - 2008/6
N2 - The dielectric material with an isolated hydrogen-bond, 5-bromo-9-hydroxyphenalenon, was studied by means of neutron and X-ray diffractions in the temperature range between 300 and 10 K. Analyses on nuclear and electron density distributions revealed a discrepancy between the two distributions of the hydrogen atom in the hydrogen-bond region, leading to a local electronic dipole moment. Both a least-square structure analysis and the density distribution analysis by the maximum entropy method confirmed that the hydrogen atom occupies two equivalent sites near the center of the hydrogen-bond through the whole temperature range, even at the lowest temperature measured, 10 K. This feature, together with previous results on calorimetric, incoherent neutron scattering and far-infrared spectrum measurements, concludes that the hydrogen atom in the hydrogen-bond is in a tunneling state over the two sites. Consequently, 5-bromo-9-hydroxyphenalenon was experimentally identified as a quantum paraelectric material.
AB - The dielectric material with an isolated hydrogen-bond, 5-bromo-9-hydroxyphenalenon, was studied by means of neutron and X-ray diffractions in the temperature range between 300 and 10 K. Analyses on nuclear and electron density distributions revealed a discrepancy between the two distributions of the hydrogen atom in the hydrogen-bond region, leading to a local electronic dipole moment. Both a least-square structure analysis and the density distribution analysis by the maximum entropy method confirmed that the hydrogen atom occupies two equivalent sites near the center of the hydrogen-bond through the whole temperature range, even at the lowest temperature measured, 10 K. This feature, together with previous results on calorimetric, incoherent neutron scattering and far-infrared spectrum measurements, concludes that the hydrogen atom in the hydrogen-bond is in a tunneling state over the two sites. Consequently, 5-bromo-9-hydroxyphenalenon was experimentally identified as a quantum paraelectric material.
KW - Isolated hydrogen-bonded system
KW - Neutron diffraction
KW - Structural analysis
KW - X-ray diffraction
UR - http://www.scopus.com/inward/record.url?scp=54349116743&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=54349116743&partnerID=8YFLogxK
U2 - 10.1143/JPSJ.77.064602
DO - 10.1143/JPSJ.77.064602
M3 - Article
AN - SCOPUS:54349116743
VL - 77
JO - Journal of the Physical Society of Japan
JF - Journal of the Physical Society of Japan
SN - 0031-9015
IS - 6
M1 - 064602
ER -