Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Fast parallel algorithms for short-range molecular dynamics

Nanocrystals are fundamental to modern science and technology. Mastery over the shape of a nanocrystal enables control of its properties and enhancement of its usefulness for a given application. Our aim is to present a comprehensive review of current research activities that center on the shape-controlled synthesis of metal nanocrystals. We begin with a brief introduction to nucleation and growth within the context of metal nanocrystal synthesis, followed by a discussion of the possible shapes that a metal nanocrystal might take under different conditions. We then focus on a variety of experimental parameters that have been explored to manipulate the nucleation and growth of metal nanocrystals in solution-phase syntheses in an effort to generate specific shapes. We then elaborate on these approaches by selecting examples in which there is already reasonable understanding for the observed shape control or at least the protocols have proven to be reproducible and controllable. Finally, we highlight a number of applications that have been enabled and/or enhanced by the shape-controlled synthesis of metal nanocrystals. We conclude this article with personal perspectives on the directions toward which future research in this field might take.

Shape‐Controlled Synthesis of Metal Nanocrystals: Simple Chemistry Meets Complex Physics?

Recent years have seen a renewed interest in the harvesting and conversion of solar energy. Among various technologies, the direct conversion of solar to chemical energy using photocatalysts has received significant attention. Although heterogeneous photocatalysts are almost exclusively semiconductors, it has been demonstrated recently that plasmonic nanostructures of noble metals (mainly silver and gold) also show significant promise. Here we review recent progress in using plasmonic metallic nanostructures in the field of photocatalysis. We focus on plasmon-enhanced water splitting on composite photocatalysts containing semiconductor and plasmonic-metal building blocks, and recently reported plasmon-mediated photocatalytic reactions on plasmonic nanostructures of noble metals. We also discuss the areas where major advancements are needed to move the field of plasmon-mediated photocatalysis forward.

Plasmonic-metal nanostructures for efficient conversion of solar to chemical energy

Nanocrystals (NCs) discussed in this Review are tiny crystals of metals, semiconductors, and magnetic material consisting of hundreds to a few thousand atoms each. Their size ranges from 2-3 to about 20 nm. What is special about this size regime that placed NCs among the hottest research topics of the last decades? The quantum mechanical coupling * To whom correspondence should be addressed. E-mail: dvtalapin@uchicago.edu. † The University of Chicago. ‡ Argonne National Lab. Chem. Rev. 2010, 110, 389–458 389

/pdf/prospects-of-colloidal-nanocrystals-for-electronic-and-3dxpyhl3r7.pdf

Prospects of Colloidal Nanocrystals for Electronic and Optoelectronic Applications

Localized Surface Plasmon Resonance Sensors

ACS Materials Letters at 1.5 Years

When Spectroscopy Met Carbon Materials: An Interview with Richard McCreery for Chemistry of Materials’ 1k Club

Strain engineering of bimetallic core@shell electrocatalysts is a promising approach to increase catalytic selectivity, activity, and durability of catalysts in electrochemical energy conversion applications [1,2]. The catalytic activity has been proposed to be controlled by the metal-ligand bond strengths [2,3]. Furthermore, surface strain has been demonstrated to be a controlling factor for the bond strength through modification of the metal-metal bond length and thus, strain is regarded as one of the most significant tuning variables available for enhancing catalytic activity. To better correlate strain at atomic-level interfaces with catalyst functionality, it is important to precisely measure the local lattice strain. Several approaches have been explored to quantify local strain: coherent X-ray diffraction, annular dark field (ADF) scanning transmission electron microscopy (STEM), and X-ray absorption spectroscopy among others [1-4]. Of all the available approaches, electron microscopy is by far the only technique that enables direct visualization of a catalyst nanoparticle’s atomic structure, allowing for the straightforward measurement of strain directly from the positions of the atomic columns. However, in reality the expected displacements due to strain are similar to the precision limits of ADF-STEM (~2pm). Additionally, scan and drift distortions are limiting factors in strain measurement derived from ADF-STEM datasets. Scanning nanodiffraction has been proposed as an alternative, robust technique for strain measurements, where the strain is calculated in the diffraction plane from the positions of the higher order diffraction disks [5]. Yet, depending on the disk fitting algorithms used, significant variations can be present in strain measurements, even when using the same underlying dataset.

/pdf/investigation-of-strain-in-core-shell-electrocatalysts-with-3c000zn8ez.pdf

Investigation of Strain in Core@shell Electrocatalysts with ADF-STEM and 4D STEM Scanning Nanodiffraction

Bismuth oxyhalides are a promising class of photocatalysts for harvesting solar energy. These materials are often synthesized in aqueous media with poor synthetic control resulting from the extremely fast nucleation and growth rates of the particles. These fast rates are caused by the rapid precipitation of bismuth salts with free halide ions. We have developed water-soluble precursors combining bismuth with either chlorine or bromine atoms in the same metal-organic complex. With the application of heat, halide ions are released, which then precipitate with bismuth ions as BiOX (X = Cl, Br). By controlling the halide ion formation rate, the nucleation and growth rates of BiOX materials can be tuned to provide synthetic control. The diverse potential of these precursors is demonstrated by synthesizing BiOX in three ways: aqueous colloidal synthesis, solid-state decomposition, and fabrication of films of BiOX via spray pyrolysis of the aqueous precursor solutions. These broadly applicable single-source precursors will enhance the ability to synthesize future BiOX materials with controlled morphologies.

Single-Source Precursors for the Controlled Aqueous Synthesis of Bismuth Oxyhalides.

ADVERTISEMENT RETURN TO ISSUEEditorialNEXTAvoiding the Empty Review: Answering “How Novel and Significant Is This Research?” as a Peer ReviewerSara E. Skrabalak*Sara E. Skrabalak*Email: [email protected]More by Sara E. Skrabalakhttps://orcid.org/0000-0002-1873-100XCite this: Chem. Mater. 2023, 35, 10, 3743–3744Publication Date (Web):May 23, 2023Publication History Received4 May 2023Published online23 May 2023Published inissue 23 May 2023https://doi.org/10.1021/acs.chemmater.3c01046Copyright © 2023 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views2014Altmetric-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 InReddit PDF (860 KB) Get e-AlertscloseSUBJECTS:Chemical structure,Mathematical methods,Physical and chemical processes,Reaction products,Testing and assessment Get e-Alerts 

https://pubs.acs.org/doi/pdf/10.1021/acs.chemmater.3c01046

Sara E. Skrabalak

Papers

ACS Materials Letters at 1.5 Years

When Spectroscopy Met Carbon Materials: An Interview with Richard McCreery for Chemistry of Materials’ 1k Club

Investigation of Strain in Core@shell Electrocatalysts with ADF-STEM and 4D STEM Scanning Nanodiffraction

Single-Source Precursors for the Controlled Aqueous Synthesis of Bismuth Oxyhalides.

Avoiding the Empty Review: Answering “How Novel and Significant Is This Research?” as a Peer Reviewer