Ferroelectric behaviour in solid croconic acid using neutron scattering and first-principles density functional theory

Mukhopadhyay, Sanghamitra; Gutmann, Matthias J.; Jura, Marek; Jochym, Dominik B.; Jiménez‐Ruiz, Mónica; Sturniolo, Simone; Refson, Keith; Fernandez-Alonso, Félix

doi:10.1016/j.chemphys.2013.10.008

Cited by 18 publications

(25 citation statements)

References 21 publications

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“…From figure 3, it is clear that the doublet at 900 cm −1 , which is similar to that observed in the INS spectrum of croconic acid, (C)-O, respectively (See figure 4). The magnitudes of blueshifts in these modes are similar to those found in croconic acid [9,10] Calculations predict that the broad hump observed in INS just above 1200 cm −1 is part of the triplet which in the calculated spectrum is blue shifted to 1300 cm −1 . Modes associated with the triplet are in-pane bending of O-H-O as mentioned above, twisted motion of H(B)-C-H(B) at the base of C-ring, and librational motion of H(B), respectively.…”

Section: Resultssupporting

confidence: 70%

“…[7][8][9][10] is blue shifted by about 150 cm −1 in the calculated spectra. These dominant vibrations, as observed in INS at 880 and 900 cm −1 , are predicted as the out-of-plane bending modes of protons for O-H(T)-O and O-H…”

mentioning

confidence: 84%

“…Strong and flexible hydrogen bonds in croconic acid crystal support a Jahn-Teller type distortion leading to strong polarisation at room temperatures [7]. Inelastic neutron scattering (INS) along with first principles density functional theory (DFT) based lattice and molecular dynamics calculations help to underpin the dynamics of protons of its hydrogen bonds [8][9][10]. As a continuation of these investigations, in this article the focus is to investigate the vibrational modes related to hydrogen bonds in CBDC (1-cyclobutene-1,2dicarboxylic acid, C 6 H 8 O 4 ), another hydrogen-bonded molecular crystal showing ferroelectric properties at room temperatures [2,4].…”

Section: Introductionmentioning

confidence: 99%

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Identification of normal modes responsible for ferroelectric properties in organic ferroelectric CBDC

Mukhopadhyay

2019

J. Phys. Commun.

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Structure and dynamics of hydrogen bonded organic ferroelectric CBDC (1-cyclobutene-1,2dicarboxylic acid, C 6 H 8 O 4 ) have been investigated using inelastic neutron scattering (INS) spectroscopy and first principles lattice dynamics. Vibrational modes of O-H-O bending, related with two different types of hydrogen bonds, inter and intra-molecular, are manifested as two sets of doublets in the range of 900-1400 cm −1 in the INS spectrum. First principles density functional theory (DFT) is used to assign these doublets to out-of-the-plane and in-plane vibrations of these two types of O-H-O bending modes. Correlating structure and dynamics we find that although the local structures of the hydrogen bonded protons are similar, their medium range order may influence their vibrational frequencies. Vibrational modes of non-hydrogen bonded protons also are assigned separately in the spectrum. Comparing the calculated and the experimental INS spectra it is predicted that hydrogen bonded O-H bonds are more anharmonic than non-hydrogen bonded C-H bonds. From the calculated Born effective charge tensor it is predicted that inter-molecular hydrogen bonds contribute more to the ferroelectric polarisation of CBDC than intra-molecular ones. A large LO-TO splitting of the O-H stretching mode at 2471 cm −1 is identified with the mode that has significant contribution to the ferroelectric polarisation. As this mode is sensitive to long range Coulomb interactions and is responsible for ferroelectric properties of the material, vibrational spectroscopy combined with DFT calculations is proposed as a characterisation tool to investigate ferroelectric properties in the CBDC molecular crystal.

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Section: Resultssupporting

confidence: 70%

mentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

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Identification of normal modes responsible for ferroelectric properties in organic ferroelectric CBDC

Mukhopadhyay

2019

J. Phys. Commun.

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“…The similarity of design also means that VISION should also enjoy negligible backgrounds. In addition, the new instrument IN1-Lagrange at ILL [12] delivers a much higher average flux than TOSCA (and possibly even more than VISION), as inferred from recent studies on this instrument by some of the authors [13,14]. However, the resolution of IN1-Lagrange EPJ Web of Conferences remains comparable to TFXA (i.e., similar to that of most currently operating instruments).…”

Section: Introductionmentioning

confidence: 99%

Monte carlo simulations of the TOSCA spectrometer: Assessment of current performance and future upgrades

Pinna

Rudić

Parker

et al. 2015

EPJ Web of Conferences

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Abstract. We describe and assess the performance of a detailed computational description of the high-resolution TOSCA spectrometer at ISIS using neutron-transport Monte Carlo simulations. Extensive calculations using the McStas software package have been performed using the present instrument geometry and compared with available experimental data. The agreement between expected and measured performance is satisfactory in terms of the incident flux spectrum, associated time structure, and spectroscopic resolution. Encouraged by these results, we also consider the upgrade of the primary spectrometer with a tapered high-m guide. This instrument development offers the exciting prospects of providing order-of-magnitude gains in detected neutron flux over the energy-transfer range of the instrument whilst preserving its outstanding spectroscopic capabilities.

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“…Dynamics in 2,4,5, Tri Bromo ImidazoleWith the confidence of the quality of implementation, the QENS data analysis interface is used to investigate the dynamics in organic ferroelectric material 2, 4, 5Br 3 imidazole[34]. The dynamics of protons in such ferroelectric materials are important to understand the mechanism of ferroelectricity at room temperatures [35][36][37][38]…”

mentioning

confidence: 99%

A modern approach to QENS data analysis in Mantid

Mukhopadhyay

Hewer

Howells

et al. 2019

Physica B: Condensed Matter

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Data analysis of Quasi-elastic Neutron Scattering (QENS) experiments often requires multiple steps involving fitting the elastic and quasi-elastic parts of spectra with several empirical functions and analytical models. Parameters of those models can be interdependent and also dependent on the momentum transfer vector Q. Here we present a modern data analysis interface dedicated for QENS data analysis implemented within the open source software Mantid. The interface has been implemented using the state-of-the-art design pattern Model-View-Presenter (MVP). The MVP, an architectural software design pattern, facilitates automated unit tests as well as decoupling of the business logic, presentation logic and the graphical interface. Several models are implemented for analysing both elastic and quasi-elastic parts of the dynamical scattering function S (Q, ω) and intermediate scattering function I(Q, t). To understand the nature of dynamics in a QENS experiments, several models are also implemented for elastic incoherent structure factor (EISF) and jump diffusions. The interface has been validated by analysing a sample of liquid water at room temperature. The nature of hydrogen bond dynam

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Ferroelectric behaviour in solid croconic acid using neutron scattering and first-principles density functional theory

Cited by 18 publications

References 21 publications

Identification of normal modes responsible for ferroelectric properties in organic ferroelectric CBDC

Identification of normal modes responsible for ferroelectric properties in organic ferroelectric CBDC

Monte carlo simulations of the TOSCA spectrometer: Assessment of current performance and future upgrades

A modern approach to QENS data analysis in Mantid

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