Hydrogen-bonded Crystals Research Articles

Cluster Theory of Glass Transition in Rb1-x(NH4)xH2PO4

A theory of glass transition in hydrogen-bonded mixed crystals of ferroelectrics and antiferroelectrics, Rb 1- x (NH 4 ) x H 2 PO 4 , is developed within the cluster approximation on the basis of Ising pseudo-spin model for the proton system. By means of the replica method, it is shown that competition between two kinds of proton ordering under the ice rule constraint leads the system to the new glass state, and glass transition temperature T g depends on x in a way characteristic to this system. The phase diagram derived theoretically is in good agreement with the experimental results in all temperature-composition plane.

An investigation into the role of chloro-substituents in hydrogen-bonded crystals: The crystal structures of the dichlorophenols

A graphical analysis has been made of hydrogen-bonding patterns and non-bonded interactions in the crystal structures of the six dichlorophenols. This shows that hydrogen bonding is the primary interaction in stabilising all the isomers, and that C⋯C and Cl⋯Cl non-bonded interactions are also important in stabilising structures characterised by a short (≈ 4 Ã) axis.

High pressure phase transitions and hydrogen-bond symmetry in ice polymorphs

A recently developed ground state variational wave function theory of hydrogen-bonded crystals is employed to investigate the high pressure behavior of several ice polymorphs. The theory accurately accounts for short and long range proton correlations and quantum mechanical tunneling, all of which are important in the high pressure regime. Attention is focused on pressure induced order–disorder phase transitions and hydrogen-bond symmetrization for the ices VII, VIII, and Ic. We find a strongly first order transition (driven by proton tunneling) at approximately 330 kbar from the antiferroelectrically ordered ice VIII phase to a highly ionized form of proton disordered ice VII. Despite the large degree of ionization, significant short range proton order remains at the transition as indicated by the bimodality of the proton charge density along the bond. The crossover to a unimodal situation, i.e., hydrogen-bond symmetrization, is predicted to occur at 450 kbar. The effects of deuterium isotope substitution on these phenomena are also studied. Calculations for the lower density cubic form of ice indicate that it may be possible to observe symmetrical hydrogen bonds in this material at a significantly lower pressure than those required for the dense ices.

Light scattering spectra of polarization fluctuations and models of the phase transition in KDP type ferroelectrics

Abstract Recent light scattering studies in KH2PO4 type hydrogen-bonded crystals are reviewed. Dynamical properties of these crystals have been discussed in terms of the coupled tunneling proton-optical phonon model up to date. Light scattering spectra in several GHz and cm−1 regions with various scattering geometries observed in KH2PO4, KD2PO4 and their mixed crystals, however, revealed that all these spectra are well analysed in terms of a coupled polarization relaxation mode-acoustic phonon system. Since most of the spontaneous polarization is due to shifts of K, P and O ions, relaxation motions of H2PO4 dipoles arc concluded to be the origin of these low-frequency spectra. Models of the phase transition mechanism are discussed on the basis of these results and other recent experimental studies including the explanation of large isotope effects in these crystals.

Structural Phase Transition and Isotope Effects in Hydrogen-Bonded Crystals

Structural Phase Transition and Isotope Effects in Hydrogen-Bonded Crystals

Phase transitions induced by proton tunneling in hydrogen-bonded crystals. Ground-state theory

A novel theory is presented for the ground-state equilibrium properties and phase behavior of hydrogen-bonded crystals in which quantum-mechanical tunneling is important. The approach is based on a variational correlated wave function and simultaneously treats short- and long-range proton correlations in addition to the quantum tunneling aspect. Application to an exactly solvable quantum spin model along with general statistical mechanical considerations suggest the theory is quantitatively reliable for many three-dimensional crystals of interest. Model calculations reveal a diverse set of possible phase behaviors as a function of applied pressure. The theory should be useful for predicting and interpreting a range of phenomena induced by high pressure (e.g., order-disorder phase transitions, dielectric properties, hydrogen-bond symmetrization) for experimentally interesting systems such as the KDP-like (potassium dihydrogen phosphate) ferroelectrics and ice polymorphs.

Thermally Stimulated Depolarisation Current Studies on Some Hydrogen-Bonded Crystals

Thermally stimulated depolarisation current (TSDC) studies are carried out in three hydrogen-bonded crystals, namely, (N2H6)SO4, (NH2)3H(SO4), and Li(NH4)SO4. These three crystals are chosen to represent three categories wherein the dipoles are induced by impurities in the crystal, the NH3 dipoles already exist in the crystal, and the crystal possesses inherent dipole moment. TSDC peaks are observed in all the three systems and their activation energies and frequency factors are evaluated. The observed peaks are explained taking into account the nature of impurity–vacancy dipoles and the dipoles inherently present in these systems. Thermisch stimulierte Depolarisationsstrome (TSDC) werden in drei Kristallen mit Wasserstoff-bindungen, (N2Hg)SO4, (NH4)3H(SO4)2 und Li(NH4SO4 untersucht. Diese drei Kristalle werden zur Darstellung dreier Kategorien gewahlt, bei denen die Dipole durch Storstellen im Kristall induziert werden, NH3-Dipole bereits im Kristall existieren und der Kristall innere Dipolmomente besitzt. TSDC-Maxima werden in allen drei Systemen beobachtet und ihre Aktivierungsenergien und Frequenzfaktoren berechnet. Die beobachteten Maxima werden unter Beriicksichtigung der Art der Storstellen–Leerstellen-Dipole und der inherent vorhandenen Dipole in diesen Systemen erklart.

ChemInform Abstract: RADICAL PAIRS IN SINGLE CRYSTALS OF PENTAERYTHRITOL. THE FORMATION OF SPATIALLY CORRELATED RADICALS IN A HYDROGEN‐BONDED CRYSTAL

Chemischer InformationsdienstVolume 14, Issue 3 Preparative Organic Chemistry ChemInform Abstract: RADICAL PAIRS IN SINGLE CRYSTALS OF PENTAERYTHRITOL. THE FORMATION OF SPATIALLY CORRELATED RADICALS IN A HYDROGEN-BONDED CRYSTAL G. NILSSON, G. NILSSONSearch for more papers by this authorA. LUND, A. LUNDSearch for more papers by this authorP.-O. SAMSKOG, P.-O. SAMSKOGSearch for more papers by this author G. NILSSON, G. NILSSONSearch for more papers by this authorA. LUND, A. LUNDSearch for more papers by this authorP.-O. SAMSKOG, P.-O. SAMSKOGSearch for more papers by this author First published: January 18, 1983 https://doi.org/10.1002/chin.198303153Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume14, Issue3January 18, 1983 RelatedInformation

Hydrogen-bonded two-dimensional molecular crystals

Hydrogen-bonded two-dimensional molecular crystals

Radical pairs in single crystals of pentaerythritol. The formation of spatially correlated radicals in a hydrogen-bonded crystal

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRadical pairs in single crystals of pentaerythritol. The formation of spatially correlated radicals in a hydrogen-bonded crystalGoesta Nilsson, Anders Lund, and Per Olof SamskogCite this: J. Phys. Chem. 1982, 86, 21, 4144–4148Publication Date (Print):October 1, 1982Publication History Published online1 May 2002Published inissue 1 October 1982https://doi.org/10.1021/j100218a011RIGHTS & PERMISSIONSArticle Views31Altmetric-Citations5LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (568 KB) Get e-Alerts

Anisotropic compressible Ising model for quasi-one-dimensional hydrogen-bonded ferroelectrics

A compressible pseudo-spin Ising model hamiltonian is used to calculate the pressure-temperature phase diagram of quasi-one-dimensional hydrogen-bonded ferroelectric crystals such as CsD 2PO 4. We assume strong effective interactions, which are treated exactly, along chains, and weak volume dependent interactions, which are treated in the mean field approximation, between chains. In agreement with the experimental findings, the phase diagram exhibits a triple point and transition lines between ferroelectric, antiferroelectric, and paraelectric phases. However, the results suggest that the Ising model may be too simple to account for the detailed form of the phase diagram of CsD 2PO 4.

A simple model for the interpretation of phase transitions in some hydrogen-bonded crystals

Abstract The principle of short range repulsive forces between neighbour protons in infinite parallel chains of hydrogen bonds is used to interpret the phase transitions in several hydrogen bonded materials which are typical for an ordering in zero to three dimensions. Atomic shifts, deuteration effects and pressure dependences of the transition temperatures are discussed.

Vertex models for the antiferroelectric transition in squaric acid

We consider two-dimensional 4- and 12-vertex models on a square lattice for the phase transition in the layered hydrogen-bonded antiferroelectric crystals H2C4O4 and its deuterated isomorph. An exact solution for the 4-vertex model, which strictly obeys the ’’ice-rules’’, leads to a vanishing free-energy. The 12-vertex model, which takes into account the single ionized configurations, gives a second order phase transition in the framework of the Bethe approximation. The high-temperature entropy of the 12-vertex model is calculated exactly and agrees with the value predicted by the Bethe approximation. An exact calculation of the partition function for a modified 12-vertex model, with a more degenerate ground state, leads to a well behaved thermodynamic potential. Also, we add a mean-field interlayer interaction to the 12-vertex model for predicting the correct low-temperature ordering in squaric acid. Some thermodynamic quantities are explicitly calculated for this model.

Correlation between two isotope effects in hydrogen-bonded crystals: transition temperature and separation of two equilibrium sites

Isotope effects in hydrogen-bonded crystals exhibiting structural phase transitions are studied systematically. A correlation exists between the relative isotopic shift of the transition temperature ΔTC/TC,H and the symmetric hydrogen-bond length O⋯O in the high-temperature phase ΔTC/TC,H is proportional to Δδ, the isotopic variation in the distance between two equilibrium positions in the symmetric bond

Green's-function theory of phase transitions in hydrogen-bonded ferroelectric crystals with pseudo-spin-lattice coupled mode model

In this paper the recent Green's-function theory of Ramkrishnan and Tanaka for studying ferroelectric phase transitions in potassium dihydrogen phosphate (KDP)-type crystals using pseudo-spin-lattice coupled mode (PLCM) model has been extended to include the effect of phonon anharmonicity and to compare the calculated results with the recent experimental data. The renormalized proton-phonon energy spectrum, Curie-Weiss constant ($C$), Curie temperature (${T}_{C}$), and the logarithmic behavior of specific heat (${C}_{v}$) calculated from the internal energy have been studied with this extended PLCM model. Our theory in particular is able to explain, along with other physical properties, the large shift of the Curie temperature in all the KDP-type crystals on deuteration compared to the small change of the Curie-Weiss constant. The latter has not been possible using the cluster satistical treatment taking into account the excited Slater-Takagi (ST) energy levels. It is also observed that, except for the specific heat, the calculated quantities (such as electrical susceptibility and Curie-Weiss constant) depend on the tunneling energy explicitly. A very good agreement between our theoretical results and those of recent experimental data indicates the suitability of the Green-function technique and the Tyablikov-type decoupling scheme for studying phase transitions in the KDP family. We have also shown that our present theory leads to a pseudo-Jahn-Teller-like mechanism in the KDP system and shows close resemblance between the topologies of the order disorder and displacive type of phase transition. It therefore indicates the possibility of a unified theory of phase transition in ferroelectric crystals. Finally the Blinc-de Gennes parameters calculated for different KDP salts have also been compared with the experimental results available.

ChemInform Abstract: CONSISTENT FORCE FIELD STUDIES OF INTERMOLECULAR FORCES IN HYDROGEN‐BONDED CRYSTALS. 1. CARBOXYLIC ACIDS, AMIDES, AND THE C:O.CNTDOT..CNTDOT..CNTDOT.H‐ HYDROGEN BONDS

Chemischer InformationsdienstVolume 10, Issue 51 Physical Organic Chemistry ChemInform Abstract: CONSISTENT FORCE FIELD STUDIES OF INTERMOLECULAR FORCES IN HYDROGEN-BONDED CRYSTALS. 1. CARBOXYLIC ACIDS, AMIDES, AND THE C:O.CNTDOT..CNTDOT..CNTDOT.H- HYDROGEN BONDS S. LIFSON, S. LIFSONSearch for more papers by this authorA. T. HAGLER, A. T. HAGLERSearch for more papers by this authorP. DAUBER, P. DAUBERSearch for more papers by this author S. LIFSON, S. LIFSONSearch for more papers by this authorA. T. HAGLER, A. T. HAGLERSearch for more papers by this authorP. DAUBER, P. DAUBERSearch for more papers by this author First published: December 18, 1979 https://doi.org/10.1002/chin.197951069AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume10, Issue51December 18, 1979 RelatedInformation

Consistent force field studies of intermolecular forces in hydrogen-bonded crystals. 1. Carboxylic acids, amides, and the C:O.cntdot..cntdot..cntdot.H- hydrogen bonds

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConsistent force field studies of intermolecular forces in hydrogen-bonded crystals. 1. Carboxylic acids, amides, and the C:O.cntdot..cntdot..cntdot.H- hydrogen bondsS. Lifson, A. T. Hagler, and P. DauberCite this: J. Am. Chem. Soc. 1979, 101, 18, 5111–5121Publication Date (Print):August 1, 1979Publication History Published online1 May 2002Published inissue 1 August 1979https://doi.org/10.1021/ja00512a001RIGHTS & PERMISSIONSArticle Views1430Altmetric-Citations444LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

Consistent force field studies of intermolecular forces in hydrogen-bonded crystals. 3. The C:O.cntdot..cntdot..cntdot.H-O hydrogen bond and the analysis of the energetics and packing of carboxylic acids

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConsistent force field studies of intermolecular forces in hydrogen-bonded crystals. 3. The C:O.cntdot..cntdot..cntdot.H-O hydrogen bond and the analysis of the energetics and packing of carboxylic acidsA. T. Hagler, P. Dauber, and S. LifsonCite this: J. Am. Chem. Soc. 1979, 101, 18, 5131–5141Publication Date (Print):August 1, 1979Publication History Published online1 May 2002Published inissue 1 August 1979https://doi.org/10.1021/ja00512a003RIGHTS & PERMISSIONSArticle Views389Altmetric-Citations170LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

Consistent force field studies of intermolecular forces in hydrogen-bonded crystals. 2. A benchmark for the objective comparison of alternative force fields

Consistent force field studies of intermolecular forces in hydrogen-bonded crystals. 2. A benchmark for the objective comparison of alternative force fields

Band shapes of infrared absorption spectra of isotopically diluted XH groups in hydrogen-bonded crystals

A model is proposed which quantitatively describes the infrared band shapes of the stretching vibrations of isotopically diluted XH groups in hydrogen-bonded crystals. The model assumes weak interactions between the high-frequency XH stretching vibration and low-frequency vibrations of the lattice. The interactions are described in the adiabatic approximation and an expression is obtained which yields band shapes at different temperatures. The model explains the observed experimental facts such as symmetric band shapes, changes of band shapes and widths with temperature, the isotopic effect and the absence of sidebands in infrared spectra.