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We welcomed 63 delegates to the University of Birmingham for a Faraday discussion on the latest techniques around NMR simulation. Lyndon Emsley was awarded the Spiers Memorial medal for his excellence in the field. Sharon Ashbrook delivered the concluding lecture to summarise the lively discussion over the three days. A good time was had by all.

We recognise Wataru Sekine who has become an Honorary Senior Research Fellow in the School of Metallurgy and Materials at the University of Birmingham.

Congratulations to Andrea for passing his PhD viva at the University of Birmingham. Andrea has been with the group since 2019, working on modelling quantum materials. We are so proud of him, and we wish him the best in all his future endeavours!

Using ab initio dynamical mean-field theory we explore the electronic and magnetic states of layered Li_xMnO₂ as a function of x, the state-of-charge. We observe a crossover from coherent to incoherent behavior on delithiation as function of state-of-charge.

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Ni-rich lithium-ion cathode materials achieve both high voltages and capacities but are prone to structural instabilities and oxygen loss. The origin of the instability lies in the pronounced oxidation of O during delithiation: for LiNiO₂, NiO₂, and the rock salt NiO, density functional theory and dynamical mean-field theory calculations based on maximally localized Wannier functions yield a Ni charge state of ca. +2, with O varying between −2 (NiO), −1.5 (LiNiO2), and −1 (NiO2). Calculated X-ray spectroscopy Ni K and O K-edge spectra agree well with experimental spectra. Using ab initio molecular dynamics simulations, we observe loss of oxygen from the (012) surface of delithiated LiNiO₂, two surface O⋅⁻ radicals combining to form a peroxide ion, and the peroxide ion being oxidized to form O₂, leaving behind two O vacancies and two O²⁻ ions. Preferential release of ¹O₂ is dictated via the singlet ground state of the peroxide ion and spin conservation.

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By including phonon-assisted transitions within plane-wave density functional theory methods for calculating the x-ray absorption spectrum (XAS), we obtain the Al K-edge XAS at 300 K for two crystalline Al2O3 phases. The 300 K XAS reproduces the pre-edge peak for α-Al2O3, which is not visible at the static lattice level of approximation. Configurations from Monte Carlo sampling of the γ-Al2O3 phase space at the 300 K XAS correctly describe two out of the three experimental peaks. We show that the second peak arises from 1s to mixed s-p transitions and is absent in the 0 K XAS. This letter serves as an insight into the electronic origins of the characteristic peaks in the Al K-edge XAS for alumina crystals. Full Article

Metal–organic magnets (MOMs), modular magnetic materials where metal atoms are connected by organic linkers, are promising candidates for next-generation quantum technologies. MOMs readily form low-dimensional structures and so are ideal systems to realize physical examples of key quantum models, including the Haldane phase, where a topological excitation gap occurs in integer-spin antiferromagnetic (AFM) chains. Thus, far the Haldane phase has only been identified for S = 1, with S ≥ 2 still unrealized because the larger spin imposes more stringent requirements on the magnetic interactions. Here, we report the structure and magnetic properties of CrCl2(pym) (pym = pyrimidine), a new quasi-1D S = 2 AFM MOM. We show, using X-ray and neutron diffraction, bulk property measurements, density-functional theory calculations, and inelastic neutron spectroscopy (INS), that CrCl2(pym) consists of AFM CrCl2 spin chains (J1 = −1.13(4) meV) which are weakly ferromagnetically coupled through bridging pym (J2 = 0.10(2) meV), with easy-axis anisotropy (D = −0.15(3) meV). We find that, although small compared to J1, these additional interactions are sufficient to prevent observation of the Haldane phase in this material. Nevertheless, the proximity to the Haldane phase together with the modularity of MOMs suggests that layered Cr(II) MOMs are a promising family to search for the elusive S = 2 Haldane phase. Full Article

Sincere congratulations to Angela for passing her PhD viva at the University of Cambridge! Having been part of the Morris Group since her MPhil, we are all so proud of her many achievements during her time in the group. We all wish her the very best in her future career!

K-ion batteries (KIBs) have the potential to offer a cheaper alternative to Li-ion batteries (LIBs) using widely abundant materials. Conversion/alloying anodes have high theoretical capacities in KIBs, but it is believed that electrode damage from volume expansion and phase segregation by the accommodation of large K-ions leads to capacity loss during electrochemical cycling. To date, the exact phase transformations that occur during potassiation and depotassiation of conversion/alloying anodes are relatively unexplored. In this work, we synthesize two distinct compositions of tin phosphides, Sn4P3 and SnP3, and compare their conversion/alloying mechanisms with solid-state nuclear magnetic resonance (SSNMR) spectroscopy, powder X-ray diffraction (XRD), and density functional theory (DFT) calculations. Ex situ31P and 119Sn SSNMR analyses reveal that while both Sn4P3 and SnP3 exhibit phase separation of elemental P and the formation of KSnP-type environments (which are predicted to be stable based on DFT calculations) during potassiation, only Sn4P3 produces metallic Sn as a byproduct. In both anode materials, K reacts with elemental P to form K-rich compounds containing isolated P sites that resemble K3P but K does not alloy with Sn during potassiation of Sn4P3. During charge, K is only fully removed from the K3P-type structures, suggesting that the formation of ternary regions in the anode and phase separation contribute to capacity loss upon reaction of K with tin phosphides. Full Article

Finite Temperature Effects on the X-ray Absorption Spectra of Crystalline Aluminas from First Principles - Angela F. Harper, Bartomeu Monserrat, and Andrew J. Morris Full Article

One-dimensional (1D) atomic chains of CsI were previously reported in double-walled carbon nanotubes with ∼0.8 nm inner diameter. Here, we demonstrate that, while 1D CsI chains form within narrow ∼0.73 nm diameter single-walled carbon nanotubes (SWCNTs), wider SWCNT tubules (∼0.8–1.1 nm) promote the formation of helical chains of CsI 2 × 1 atoms in cross-section. These CsI helices create complementary oval distortions in encapsulating SWCNTs with highly strained helices formed from strained Cs2I2 parallelogram units in narrow tubes to lower strain Cs2I2 units in wider tubes. The observed structural changes and charge distribution were analyzed by density-functional theory and Bader analysis. CsI chains also produce conformation-selective changes to the electronic structure and optical properties of the encapsulating tubules. The observed defects are an interesting variation from defects commonly observed in alkali halides as these are normally associated with the Schottky and Frenkel type. The energetics of CsI 2 × 1 helix formation in SWCNTs suggests how these could be controllably formed. Full Article

A big welcome to Mario Antonio Ongkiko, a new PhD student under the EPSRC Centre for Doctoral Training in Topological Design.

Congratulations to Chris Owen for receives the Rollason Memorial Prize for highest mark in the final year project 2020/21. The prize was awarded for his work on ‘Modelling an Amorphous Zirconia ALD Coating using Density-Functional Theory’.

As part of the 2021 virtual CamFest, Angela submitted a video explanation for the general public about how she uses computational physics to study Li-ion batteries as part of her PhD.

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Jordan Dorrell was awarded the Midlands Computational Chemistry Meeting 2021 best poster prize. Jordan presented a poster titled “Machine Learning Random Structure Searching for Li-Ni-S Cathode Discovery”.

The properties of materials depend heavily on their atomistic structure; knowledge of the possible stable atomic configurations that define a material is required to understand the performance of many technologically and ecologically relevant devices, such as those used for energy storage (A. F. Harper et al., 2020; Marbella et al., 2018). First-principles crystal structure prediction (CSP) is the art of finding these stable configurations using only quantum mechanics (A. F. Harper, Evans, et al., 2020). Density-functional theory (DFT) is a ubiquitous theoretical framework for finding approximate solutions to quantum mechanics; calculations using a modern DFT package are sufficiently robust and accurate that insight into real materials can be readily obtained. The computationally intensive work is performed by well-established, low-level software packages, such as CASTEP (Clark et al., 2005) or Quantum Espresso (Giannozzi et al., 2009), which are able to make use of modern highperformance computers. In order to use these codes easily, reliably and reproducibly, many high-level libraries have been developed to create, curate and manipulate the calculations from these low-level workhorses; matador is one such framework.

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Complex crystal structures with subtle atomic-scale details are now routinely solved using complementary tools such as X-ray and/or neutron scattering combined with electron diffraction and imaging. Identifying unambiguous atomic models for oxyfluorides, needed for materials design and structure–property control, is often still a considerable challenge despite their advantageous optical responses and applications in energy storage systems. In this work, NMR crystallography and single-crystal X-ray diffraction are combined for the complete structure solution of three new compounds featuring a rare triangular early transition metal oxyfluoride cluster, [Mo3O4F9]5–. After framework identification by single-crystal X-ray diffraction, 1D and 2D solid-state 19F NMR spectroscopy supported by ab initio calculations are used to solve the structures of K5[Mo3O4F9]·3H2O (1), K5[Mo3O4F9]·2H2O (2), and K16[Mo3O4F9]2[TiF6]3·2H2O (3) and to assign the nine distinct fluorine sites in the oxyfluoride clusters. Furthermore, 19F NMR identifies selective fluorine dynamics in K16[Mo3O4F9]2[TiF6]3·2H2O. These dual scattering and spectroscopy methods are used to demonstrate the generality and sensitivity of 19F shielding to small changes in bond length, on the order of 0.01 Å or less, even in the presence of hydrogen bonding, metal–metal bonding, and electrostatic interactions. Starting from the structure models, the nature of chemical bonding in the molybdates is explained by molecular orbital theory and electronic structure calculations. The average Mo–Mo distance of 2.505 Å and diamagnetism in 1, 2, and 3 are attributed to a metal–metal bond order of unity along with a 1a21e4 electronic ground state configuration for the [Mo3O4F9]5− cluster, leading to a rare trimeric spin singlet involving d2 Mo4+ ions. The approach to structure solution and bonding analysis is a powerful strategy for understanding the structures and chemical properties of complex fluorides and oxyfluorides.

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Niobium tungsten oxides with crystallographic shear structures form a promising class of high-rate Li-ion anode materials. Lithium diffusion within these materials is studied in this work using density functional theory calculations, specifically nudged elastic band calculations and ab initio molecular dynamics simulations. Lithium diffusion is found to occur through jumps between 4-fold coordinated window sites with low activation barriers (80–300 meV) and is constrained to be effectively one-dimensional by the crystallographic shear planes of the structures. We identify a number of other processes, including rattling motions with barriers on the order of the thermal energy at room temperature, and intermediate barrier hops between 4-fold and 5-fold coordinated lithium sites. We demonstrate differences regarding diffusion pathways between different cavity types; within the ReO3-like block units of the structures, cavities at the corners and edges host more isolated diffusion tunnels than those in the interior. Diffusion coefficients are found to be in the range of 10^–12 to 10^–11 m² s^–1 for lithium concentrations of 0.5 Li/TM. Overall, the results provide a complete picture of the diffusion mechanism in niobium tungsten oxide shear structures, and the structure–property relationships identified in this work can be generalized to the entire family of crystallographic shear phases.

Full Article - One of the top 20 most downloaded articles in April in Chemistry of Materials.

News Article - A news article has been written on this publication.

Li₇La₃Zr₂O₁₂ (LLZO) garnets are among the most promising solid electrolytes for next-generation all-solid-state Li-ion battery applications due to their high stabilities and ionic conductivities. To help determine the influence of different supervalent dopants on the crystal structure and site preferences, we combine solid-state 17O, 27Al, and 71Ga magic angle spinning (MAS) NMR spectroscopy and density-functional theory (DFT) calculations. DFT-based defect configuration analysis for the undoped and Al and/or Ga-doped LLZO variants uncovers an interplay between the local network of atoms and the observed NMR signals. Specifically, the two characteristic features observed in both 27Al and 71Ga NMR spectra result from both the deviations in the polyhedral coordination/site-symmetry within the 4-fold coordinated Li1/24d sites (rather than the doping of the other Li2/96h or La sites) and with the number of occupied adjacent Li2 sites that share oxygen atoms with these dopant sites. The sharp 27Al and 71Ga resonances arise from dopants located at a highly symmetric tetrahedral 24d site with four corner-sharing LiO4 neighbors, whereas the broader features originate from highly distorted dopant sites with fewer or no immediate LiO4 neighbors. A correlation between the size of the 27Al/71Ga quadrupolar coupling and the distortion of the doping sites (viz. XO4/XO5/XO6 with X = {Al/Ga}) is established. 17O MAS NMR spectra for these systems provide insights into the oxygen connectivity network: 17O signals originating from the dopant-coordinating oxygens are resolved and used for further characterization of the microenvironments at the dopant and other sites.

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Angela Harper is a PhD candidate at the Cavendish Laboratory, a member of Churchill College, and a Gates Cambridge Scholar. Here, she tells us about her work in renewable energy, setting up a Girls in STEM programme while she was an undergraduate in North Carolina, and the importance of role models when pursuing a career in STEM.

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Wadsley–Roth crystallographic shear phases form a family of compounds that have attracted attention due to their excellent performance as lithium-ion battery electrodes. The complex crystallographic structure of these materials poses a challenge for first-principles computational modeling and hinders the understanding of their structural, electronic and dynamic properties. In this article, we study three different niobium–tungsten oxide crystallographic shear phases (Nb12WO33, Nb14W3O44, Nb16W5O55) using an enumeration-based approach and first-principles density-functional theory calculations. We report common principles governing the cation disorder, lithium insertion mechanism, and electronic structure of these materials. Tungsten preferentially occupies tetrahedral and block-central sites within the block-type crystal structures, and the local structure of the materials depends on the cation configuration. The lithium insertion proceeds via a three-step mechanism, associated with an anisotropic evolution of the host lattice. Our calculations reveal an important connection between long-range and local structural changes: in the second step of the mechanism, the removal of local structural distortions leads to the contraction of the lattice along specific crystallographic directions, buffering the volume expansion of the material. Niobium–tungsten oxide shear structures host small amounts of localized electrons during initial lithium insertion due to the confining effect of the blocks, but quickly become metallic upon further lithiation. We argue that the combination of local, long-range, and electronic structural evolution over the course of lithiation is beneficial to the performance of these materials as battery electrodes. The mechanistic principles we establish arise from the compound-independent crystallographic shear structure and are therefore likely to apply to niobium–titanium oxide or pure niobium oxide crystallographic shear phases.

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Abstract: The prediction of topological preferences and polymorph stability remains a challenge for the design of metal-organic frameworks (MOFs) exhibiting a rich topological landscape, such as zeolitic imidazolate frameworks (ZIFs). Here, we have used mechanochemical screening and calorimetry to test the ability of dispersion-corrected periodic density functional theory (DFT) to accurately survey the topological landscape, as well as quantitatively evaluate polymorph stability, for a previously not synthesized ZIF composition. Theoretical calculations were used to obtain an energy ranking and evaluate energy differences for a set of hypothetical, topologically-distinct structures of a fluorine-substituted ZIF. Calculations were then experimentally validated via mechanochemical screening and calorimetry which confirmed two out of three theoretically anticipated topologies, including a fluorinated analogue of the popular ZIF-8, while revealing an excellent match between the measured and theoretically calculated energetic difference between them. The results, which speak strongly in favor of ability of dispersion-corrected periodic DFT to predict the topological landscape of new ZIFs, also reveal the ability to use peripheral substituents on the organic linker to modify the framework thermodynamic stability.

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The first CASTEP Users Meeting was held this week in Birmingham, and organised by Andrew and Phil Hasnip. The meeting was a success, with speakers travelling from as far as Taiwan to attend the workshop. At the meeting, one of the Morris group PhD students, Angela Harper, took home the first place poster prize for her work on “Electronic Structure and Properties of Transition Metal Phosphides”. Featured in the image here is Bjoern Winkler from Goethe University, Frnakfurt, Germany, giving the first talk of the workshop on “Understanding phase transitions using CASTEP”. Andrew, and the rest of the CASTEP community are looking forward to hosting more workshops such as this one in the coming years, to make this an annual occurance. This is in addition to the CASTEP Workshop held each year in August for new users and CASTEP developers.

For more information on CASTEP, and to stay informed about upcoming workshops, visit the website

Atoms stick together to make the world around us through a set of different atom-atom interactions called bonds. Without atomic bonding, the universe would be just be one large gas with nothing solid in it at all.

The text-book four types of atomic bonding are ionic (think table salt), covalent (silicon chips), metallic (steels, iron etc) and van der Waals (how geckos stick to the ceiling). However, there is a fifth kind of bonding, called a non-covalent directional interaction. It is responsible for water’s unusual properties such as expanding on freezing (most liquids shrink) and having a high boiling point compared to other molecular liquids.

We care about this fifth kind of bonding as it can stick molecules together into molecular crystals which have a wide variety of uses, for example, capturing carbon dioxide from the atmosphere, detecting trace impurities and toxins, sensing biomolecules and a vast collection of pharmaceuticals. It’s similar to molecular Lego – the more different ways we can stick bricks together, the more useful (and fun!) materials we can make.

The halogen elements such as fluorine, chlorine, bromine, and iodine can form these fifth-kind bonds. Up until now they were thought to only bond to small, compact atoms like nitrogen or oxygen, limiting the ways molecular crystals could be assembled. In this international collaboration between UK, Canada and Croatia we show that we can make molecular crystals by bonding the halogen iodine to the much heavier phosphorus, arsenic and antimony atoms, some 2, 5 and 8 times more massive than oxygen respectively.

This research paves the way for many new molecular crystals with fantastic new properties. We show, for example, colossal expansion in a crystals with I…Sb bonds on heating.

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In a December 2018 Virtual Issue of the ACS journal Inorganic Chemistry entitled “Emerging Investigators in Solid-State Inorganic Chemistry” the Morris group received recognition for their work on battery anode materials using ab initio random structure searching (AIRSS). The journal highlighted the Morris group’s work on Li/Sn and Li/Sb systems, which helped to identify the phases of these anode materials which form during battery cycling. Within the issue, young investigators and groups were mentioned who “…have started their independent laboratories in the past 5–8 years and published notable papers in the selected journals Inorganic Chemistry, Chemistry of Materials, and Journal of the American Chemical Society since 2016.” As the group continues to search for better battery materials, identify new phases of helical phosphorus, and develop new methods for density-functional theory, they continue to forge ahead in the field of solid-state inorganic chemistry.

See the full editorial here.

Read the Li/Sn Li/Sb paper here.

Indium oxide is a wide band gap semiconductor that provides the platform for most n-type transparent conductors. Optical absorption is dominated by a strong edge starting at the optical gap around 3.7 eV, but the material also exhibits a prominent absorption tail starting around 2.7 eV. We use first principles methods to show that this tail arises from interband transitions that are dipole forbidden at the static lattice level, but become dipole allowed via a dynamical symmetry breaking induced by nuclear motion. We also report the temperature dependence of the absorption onset, which exhibits a redshift with heating, driven by a combination of electron-phonon coupling and thermal expansion. We argue that the role of dynamical symmetry breaking in optical absorption is a general feature of semiconductors and that the computational design of novel materials for optical applications, ranging from transparent conductors to solar cells, should incorporate the lattice dynamics of the crystal.

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He has completed the PhD in Physics from the University of Cambridge!

A surge in interest of oxide‐based materials is testimony for their potential utility in a wide array of device applications and offers a fascinating landscape for tuning the functional properties through a variety of physical and chemical parameters. In particular, selective electronic/defect doping has been demonstrated to be vital in tailoring novel functionalities, not existing in the bulk host oxides. Here, an extraordinary interstitial doping effect is demonstrated centered around a light element, boron (B). The host matrix is a novel composite system, made from discrete bulk LaAlO3:LaBO3 compounds. The findings show a spontaneous ordering of the interstitial B cations within the host LaAlO3 lattices, and subsequent spin‐polarized charge injection into the neighboring cations. This leads to a series of remarkable cation‐dominated electrical switching and high‐temperature ferromagnetism. Hence, the induced interstitial doping serves to transform a nonmagnetic insulating bulk oxide into a ferromagnetic ionic–electronic conductor. This unique interstitial B doping effect upon its control is proposed to be as a general route for extracting/modifying multifunctional properties in bulk oxides utilized in energy and spin‐based applications.

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The properties and applications of metal-organic frameworks (MOFs) are strongly dependent on the nature of the metals and linkers employed, along with the specific conditions employed during synthesis. Al-fumarate, trademarked as Basolite A520, is a porous MOF that incorporates aluminum centers along with fumarate linkers, and is a promising material for applications involving adsorption of gases such as CO2. In this work, the solvothermal synthesis and detailed characterization of the gallium and indium fumarate MOFs (Ga-fumarate, In-fumarate) are described. Using a combination of powder X-ray diffraction, Rietveld refinements, solid-state NMR spectroscopy, infrared spectroscopy, and thermogravimetric analysis, the topologies of Ga-fumarate and In-fumarate are revealed to be analogous to Al-fumarate. Ultra-wideline 69Ga, 71Ga and 115In NMR experiments at 21.1 T strongly support our refined structure. Adsorption isotherms show that the Al-, Ga-, and In-fumarate MOFs all exhibit an affinity for CO2, with Al-fumarate the superior adsorbent at 1 bar and 273 K. Static direct excitation and cross-polarized 13C NMR experiments permit investigation of CO2 adsorption locations, binding strengths, motional rates, and motional angles that are critical to increasing adsorption capacity and selectivity in these materials. Conducting the synthesis of the indium-based framework in methanol demonstrates a simple route to introduce porous hydrophobicity into a MIL-53-type framework, by incorporation of metal-bridging –OCH3 groups in the MOF pores.

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Can attended the 2018 Physics by the Lake summer school and won a poster prize for poster “First-Principles Study of Complex Oxides”

Nanostructuring, e.g., reduction of dimensionality in materials, offers a viable route toward regulation of materials electronic and hence functional properties. Here, we present the extreme case of nanostructuring, exploiting the capillarity of single-walled carbon nanotubes (SWCNTs) for the synthesis of the smallest possible SnTe nanowires with cross sections as thin as a single atom column. We demonstrate that by choosing the appropriate diameter of a template SWCNT, we can manipulate the structure of the quasi-one-dimensional (1D) SnTe to design electronic behavior. From first principles, we predict the structural re-formations that SnTe undergoes in varying encapsulations and confront the prediction with TEM imagery. To further illustrate the control of physical properties by nanostructuring, we study the evolution of transport properties in a homologous series of models of synthesized and isolated SnTe nanowires varying only in morphology and atomic layer thickness. This extreme scaling is predicted to significantly enhance thermoelectric performance of SnTe, offering a prospect for further experimental studies and future applications.

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Deadline 30 April 2018. More details here

Experimental and Theoretical Investigation of Structures, Stoichiometric Diversity, and Bench Stability of Cocrystals with a Volatile Halogen Bond Donor

We present a combined experimental and theoretical study of the structures and bench stability of halogen-bonded cocrystals involving the volatile halogen bond donor octafluoro-1,4-diiodobutane, with phenazine and acridine as acceptors. Cocrystallization experiments using mechanochemistry and solution crystallization revealed three chemically and structurally distinct cocrystals. Whereas only one cocrystal form has been observed with acridine, cocrystallization with phenazine led to two stoichiometrically different cocrystals, in which phenazine employs either one or two nitrogen atoms per molecule as halogen bond acceptor sites. Cocrystal stability was evaluated experimentally by simultaneous thermogravimetric analysis and differential thermal analysis or differential scanning calorimetry, real-time powder X-ray diffraction monitoring of cocrystals upon storage in open air, and theoretically by using dispersion-corrected periodic density functional theory. The use of real-time powder X-ray diffraction enabled the comparison of rates of cocrystal decomposition, and the observed trends in cocrystal stability were reproduced by the ranking of theoretically calculated cocrystal decomposition enthalpies. Whereas all cocrystals eventually lose the volatile halogen bond donor upon storage in open air or by heating, these experimental and theoretical studies show that the cocrystal of acridine is the most stable, in agreement with its more basic properties. The stoichiometric variations of the phenazine cocrystal also exhibit a notable difference in stability, with the cocrystal containing the halogen bond acceptor and donor in a 1:1 stoichiometric ratio being of particularly low stability, decomposing in open air within minutes.

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“Seeing” individual atoms is a tricky business. At such tiny length scales illumination by individual packets of light, called photons, will not work. Their wavelength, around 500 nanometres, (about 150th of a human hair) is simply too large to resolve atomic scale features in materials. To see how nature works at the atomic scale, transmission electron microscopy (TEM) uses a shorter wavelength particle, the electron. However, in the life-sciences this technique has proved unsuitable. Many biological molecules are too delicate: imaging them in an electron beam is like imaging a Ming vase with an artillery barrage.

The citation states that the award is “for significant contributions to printed electronics research and outstanding leadership of the Society of Physics Students and Society of Women in STEM fields.” More information can be found on the APS website

Martin becomes the first AJM group member to survive submit a PhD thesis, “'’Ab initio’’ anode materials discovery for Li- and Na-ion batteries”.

n the pursuit of high-capacity electrochemical energy storage, a promising domain of research involves conversion reaction schemes, wherein electrode materials are fully transformed during charge and discharge. There are, however, numerous difficulties in realizing theoretical capacity and high rate capability in many conversion schemes. Here we employ operando studies to understand the conversion material FeS2, focusing on the local structure evolution of this relatively reversible material. X-ray absorption spectroscopy, pair distribution function analysis, and first-principles calculations of intermediate structures shed light on the mechanism of charge storage in the Li–FeS2 system, with some general principles emerging for charge storage in chalcogenide materials. Focusing on second and later charge/discharge cycles, we find small, disordered domains that locally resemble Fe and Li2S at the end of the first discharge. Upon charge, this is converted to a Li–Fe–S composition whose local structure reveals tetrahedrally coordinated Fe. With continued charge, this ternary composition displays insertion–extraction behavior at higher potentials and lower Li content. The finding of hybrid modes of charge storage, rather than simple conversion, points to the important role of intermediates that appear to store charge by mechanisms that more closely resemble intercalation.

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The electrical conductivity of metallic carbon nanotubes (CNTs) quickly saturates with respect to bias voltage due to scattering from a large population of optical phonons. The decay of these dominant scatterers in pristine CNTs is too slow to offset an increased generation rate at high voltage bias. We demonstrate from first principles that encapsulation of one-dimensional atomic chains within a single-walled CNT can enhance the decay of “hot” phonons by providing additional channels for thermalization. Pacification of the phonon population growth reduces the electrical resistivity of metallic CNTs by 51% for an example system with encapsulated beryllium.

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Many congratulations to Nathalie, who will be starting a PhD at the University of Bern next year.

Congratulations to Monica, who will be starting the MPhil in Scientific Computing in October. During her degree,

She will now jet off to Stanford to start her PhD — best of luck Connie!

The group is advertising a one-year (in the first instance) postdoctoral position. This project focuses on developing new algorithms to determine structural similarity in crystalline materials, and for developing new in silico approaches to determining oxide ion conductivity in materials. For more information see [http://www.jobs.cam.ac.uk/job/10698/ here] or contact Dr Andrew Morris.

Fluorescein is known to exist in three tautomeric forms defined as quinoid, zwitterionic, and lactoid. In the solid state, the quinoid and zwitterionic forms give rise to red and yellow materials, respectively. The lactoid form has not been crystallized pure, although its cocrystal and solvate forms exhibit colors ranging from yellow to green. An explanation for the observed colors of the crystals is found using a combination of UV/Vis spectroscopy and plane‐wave DFT calculations. The role of cocrystal coformers in modifying crystal color is also established. Several new crystal structures are determined using a combination of X‐ray and electron diffraction, solid‐state NMR spectroscopy, and crystal structure prediction (CSP). The protocol presented herein may be used to predict color properties of materials prior to their synthesis.

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PhD Student Martin Mayo invited to speak about his work on NMR predictions of lithium-ion batteries to the IoP BRSG: The Magnetic Resonance Group summer meeting.

The collaboration between this Group and the Warwick NPCM group has a new website. The global demand for smaller and more energy efficient devices has been sustained by a steady decrease in the scale on which silicon microelectronics can be manufactured. To continue this trend beyond the mid 2020s devices with dimensions of just 1-2nm will be required, likely using alternatives to silicon.

The centre will cover many aspects of fundamental physics, including advanced scientific computing, the theory of condensed matter, advanced materials and the physics of biology and medicine. This will build upon the research from the Winton Programme and “will not be conventional research or ‘business as usual’, but a major effort to go beyond the boundaries of traditional physical science concepts”

Connie will be working on novel anode materials for lithium ion batteries. Prior to coming to Cambridge, she completed my BS in Physics at the California Institute of Technology in the US. Her research experience up to this point has been diverse including biochemical diagnostics, defence technologies, and iron-cathode lithium-ion batteries.

Using software to predict the characteristics of materials before they’re synthesised in order to guide and interpret experiments, the researchers successfully predicted the structures of a series of lithium silicides, an important step in understanding batteries made of silicon, and have also predicted new structures for a battery based on germanium. Thermodynamically stable lithium silicides and germanides from density-functional theory calculations

This appointment coincides with [http://gow.epsrc.ac.uk/NGBOViewGrant.aspx?GrantRef

The high theoretical gravimetric capacity of the Li-S battery system makes it an attractive candidate for numerous energy storage applications. In practice, cell performance is plagued by low practical capacity and poor cycling. In an effort to explore the mechanism of the discharge with the goal of better understanding performance, we examine the Li-S phase diagram using computational techniques and complement this with an in situ 7 Li NMR study of the cell during discharge. Ab Initio Structure Search and in Situ 7Li NMR Studies of Discharge Products in the Li-S Battery System

Who won a prize for his poster at the SMARTER4 conference in Durham, UK.