Publications

Chemistry of oxide superconductors

Chemistry of high-temperature oxide superconductors The role of crystal chemistry for generation of high-Twc oxide superconductors Ba(Pb,Bi)Ow3 superconductors and their relationship to the copper oxide based superconductors Chemistry and high-Twc superconductivity in the La-Ba-Cu-O system Synthesis, structural chemistry and properties of YBAw2Cuw3Ow7-x High-Twc superconductivity in LnBaw2Cuw3Ow7 (Ln = La-Yb, Y) compounds Chemistry-Twc relations in oxide superconductors Thermal decomposition studies of YBAw2CUw3Ow7-x using beam modulation mass spectrometry Kinetics of oxygen uptake in YBaw2Cuw3 Owx The role of oxygen in YBaw2Cuw3Ow7-(SY) Are one-dimensional structural features essential for superconductivity at 90 K Isoelectronic analogs of the high temperature oxide superconductor Substitutional chemistry of the 1:2:3 phase and studies of the Yw2O w3-SrO-CuO phase diagram Theory of superconductivity in systems with strong coulomb correlations, with applications to the organic and oxide superconductors Raman scattering studies of the copper-oxygen vibrations and oxygen order in La, Y-Ba, Sr-Cu oxides A simple method to prepare high-Twc superconducting thin films: pulsed laser deposition High-temperature superconductivity in bismuth and thallium cuprates.

An Experimental Charge Density Study of the Effect of the Noncentric Crystal Field on the Molecular Properties of Organic NLO Materials

The structure, packing, and charge distribution in molecules of nonlinear optical materials have been analysed with reference to their counterparts in centrosymmetric structures based on low temperature X-ray measurements. The systems studied are the centric and noncentric polymorphs of 5-nitrouracil as well as the diamino, dithio, and thioamino derivatives of 1,1-ethylenedicarbonitrile; the latter possesses a noncentric structure. The molecular structure of 5-nitrouracil is invariant between the two forms, while the crystal packing is considerably different, leading to dimeric N-H·∙∙O rings in the centric polymorph and linear chains in noncentric one. There is an additional C-H·∙∙O contact in the centric form with a significant overlap of the electrostatic potentials between the alkenyl hydrogen atom and an oxygen atom of the nitro group. The dipole moment of 5-nitrouracil in the noncentric form is much higher (μ=9 D) than in the centric form (≈6 D). Among the 1,1-ethylenedicarbonitriles, there is an increased charge separation in the noncentric thioamino derivative, leading to an enhanced dipole of 15 D compared to the centric diamino (5 D) and dithio (6 D) derivatives. The effect of the crystal field is borne out by semiempirical AM1 calculations on the two systems. Dipole moments calculated for the molecules in the frozen geometries match closely with those obtained for centric crystals from the experimental charge densities. The calculated values of the dipole moment in the frozen or optimized geometries in the noncentric structures are, however, considerably lower than the observed value. Furthermore, the conformation of the S-CH(3) group in the noncentric crystal is anti with respect to the central C=C bond while the syn conformation is predicted for the free molecule in the optimized geometry.

Analysis of EXAFS data of complex systems

No abstract is provided for this article.

Intergrowth structures in inorganic solids: A new class of materials

No abstract is provided for this article.

Selective generation of single-walled carbon nanotubes with metallic, semiconducting and other unique electronic properties

As-synthesized single-walled carbon nanotubes (SWNTs) are mixtures of semiconducting and metallic species and separation of the two is of crucial importance for many applications. In this article, the methods employed for the enrichment of semiconducting and metallic SWNTs are presented, along with possible procedures to prepare either of the species selectively. Equally important are the methods for chirality selection. The discovery of metal-semiconductor transitions in SWNTs induced by interaction with electron donor and acceptor molecules is not only of academic interest, but may also find applications. Synthesis of Y-junction SWNTs with unique electronic properties at the junction is yet to be fully accomplished.

Raman study of the high‐temperature phase transition of malonic acid

The Raman spectra of the high‐temperature (α) phase of crystalline malonic acid, CH 2 (COOH) 2 , and its deuteriated derivative, CD 2 (COOD) 2 , have been investigated at 370 K in the wavenumber shift range 0–4000 cm −1 . An assignment of the internal and external vibrations is given. Comparison of the infrared and Raman spectra of the α and β phases shows that the high‐temperature phase (α) consists of quivalent centrosymmetric dimer rings and that the corresponding space group is C  C2/c with molecules occupyging C 2 sites. The temperature dependence of various Raman lines, in particular those due to lattice modes, indicates that the phase transition is of first order and that during the transition, reorientation of the molecules about the c axis is strongly coupled with the low‐frequency torsional (γOH…O) and librational modes.

CCDC 613534: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An Electron Diffraction Investigation of the Molecular Structure of Trichloroacetonitrile¹

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAn Electron Diffraction Investigation of the Molecular Structure of Trichloroacetonitrile1R. L. Livingston, W. L. Page, and C. N. R. RaoCite this: J. Am. Chem. Soc. 1960, 82, 19, 5048–5051Publication Date (Print):October 1, 1960Publication History Published online1 May 2002Published inissue 1 October 1960https://pubs.acs.org/doi/10.1021/ja01504a010https://doi.org/10.1021/ja01504a010research-articleACS PublicationsRequest reuse permissionsArticle Views46Altmetric-Citations8LEARN 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 InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

C. N. R. Rao Festschrift

ADVERTISEMENT RETURN TO ISSUEArticleNEXTC. N. R. Rao FestschriftC. Angell, B. Bagchi, A. Buckingham, Sir John Thomas, and C. N. R. RaoCite this: J. Phys. Chem. 1994, 98, 37, 9083–9096Publication Date (Print):September 1, 1994Publication History Published online10 September 2003Published inissue 1 September 1994https://pubs.acs.org/doi/10.1021/j100088a600https://doi.org/10.1021/j100088a600research-articleACS PublicationsRequest reuse permissionsArticle Views355Altmetric-Citations-LEARN 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 InRedditEmail Other access options Get e-Alerts

Facile C−O Bond Scission in Alcohols on Zn Surfaces

Interaction of methanol, ethanol, and 2-propanol with polycrystalline as well as (0001) surfaces of Zn has been investigated by photoelectron spectroscopy and vibrational energy loss spectroscopy. All the alcohols show evidence for the condensed species along with the chemisorbed species at 80 K. With increase in temperature to ∼120 K, the condensed species desorbs, leaving the chemisorbed species which decomposes to give the alkoxy species. The alkoxy species is produced increasingly at lower temperatures as we go from methanol to 2-propanol, the 2-propoxy species occurring even at 80 K. The alkoxy species undergo C−O bond scission giving rise to a hydrocarbon species and oxygen. The C−O bond cleavage occurs at a relatively low temperature of ∼150 K. The effect of preadsorbed oxygen is to stabilize the methoxy species and prevent C−O bond scission. On the other hand, coadsorption of oxygen with methanol favors the formation of the methoxy species and gives rise to hydrocarbon species arising from the C−O bond scission even at 80 K.

Infrared spectroscopy as a probe for the development of secondary structure in the amino‐terminal segment of alamethicin

No abstract is provided for this article.

CCDC 283067: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Isolation and characterization of nanosheets containing few layers of the Aurivillius family of oxides and metal-organic compounds

Nanosheets containing few-layers of ferroelectric Aurivillius family of oxides, Bi2 A n−1 B n O3n+3 (where A=Bi3+, Ba2+ etc. and B=Ti4+, Fe3+ etc.) with n=3, 4, 5, 6 and 7 have been prepared by reaction with n-butyllithium, followed by exfoliation in water. The few-layer samples have been characterized by Tyndall cones, atomic force microscopy, optical spectroscopy and other techniques. The few-layer species have a thickness corresponding to a fraction of the c-parameter along which axis the perovskite layers are stacked. Magnetization measurements have been carried out on the few-layer samples containing iron. Few-layer species of a few layered metal-organic compounds have been obtained by ultrasonication and characterized by Tyndall cones, atomic force microscopy, optical spectroscopy and magnetic measurements. Significant changes in the optical spectra and magnetic properties are found in the few-layer species compared to the bulk samples. Few-layer species of the Aurivillius family of oxides may find uses as thin layer dielectrics in photovoltaics and other applications.

Sivaraj Ramaseshan (1923 - 2003): a tribute

An Investigation of Two-Dimensional Arrays of Thiolized Pd Nanocrystals

Two-dimensional arrays of Pd nanocrystals of varying diameters (1.8−6.0 nm) have been obtained after thiolization with alkane thiols of different chain lengths (C4−C16). The stability and structure of these arrays have been explained in terms of the ratio of the particle diameter (d) and the alkane chain length (l). The experimental d−l phase diagram finds support from model calculations, which treat the thiolized nanocrystals as soft spheres. Generally, a d/l value between 1.5 and 3.8 gives crystalline arrays extended over several microns. For d/l values smaller than 1.5 and greater than 4.0, the nanocrystal arrays are disordered or form low-order structures.

Superconductivity in modulation-free BiPbSr 2 Ln 1-x C a xCu 2 O 8 (Ln = Y or rare earth)

No abstract is provided for this article.

Metal–Insulator Transitions in Anion-Excess <font>LaMnO</font>_3+δ Controlled by the <font>Mn</font>⁴⁺ Content

No abstract is provided for this article.

Spectroscopic Studies of the Hydrogen Bond

Since the publication of the proceedings of the Ljubljana symposium on hydrogen bonding by Hadzi [1] and the excellent book on the hydrogen bond by Pimentel and McClellan [2], a very large number of publications on the spectroscopic studies of hydrogen bonding have appeared in the literature. The present authors prepared a review on hydrogen bonding covering the period 1958–1963 for limited circulation [3]. In view of the very enthusiastic reception for this review by a number of workers and also the vast amount of published information on the subject after 1963, it was considered valuable to present an up-to-date review on the subject. The present review covers the period from 1958 to 1967 and embodies most of the studies on the hydrogen bond employing spectroscopic methods. The review does not include studies on crystals and macromolecules; hydrogen bonding in crystals has been recently reviewed by Hamilton and Ibers [4]. Electronic theories of the hydrogen bond have been reviewed by Bratoz [5]. Even though we have attempted to write a comprehensive review to include most of the published work on spectroscopic studies, it is possible that we have missed some of the papers in this field; we apologize for such oversights and omissions which become unavoidable in such an undertaking.