Bernadette Cladek, Yuanpeng Zhang, Russell Maier, Bruce Ravel, Matthew G. Tucker, Igor Levin
{"title":"利用中子全散射数据完善整个纳米粒子的方法和挑战","authors":"Bernadette Cladek, Yuanpeng Zhang, Russell Maier, Bruce Ravel, Matthew G. Tucker, Igor Levin","doi":"10.1107/S1600576724004321","DOIUrl":null,"url":null,"abstract":"<p>This study considers critical data reduction steps and data analysis approaches required to determine explicitly the atomic arrangements in nanoparticles from time-of-flight neutron total scattering. A practical procedure is described for removing parasitic backgrounds caused by the incoherent scattering of hydrogen inevitably present in most nanoparticle samples and normalizing the recovered coherent scattering intensities onto an absolute scale. A model-free analysis is presented of a pair-distribution function derived from total scattering that can be used to determine thermal expansion coefficients and particle sizes directly from experimental data without knowledge of the material's structure. Finally, atomistic whole-nanoparticle refinements of yttrium-doped ceria nanoparticles from neutron total-scattering data are demonstrated using the reverse Monte Carlo method implemented in the <i>RMCProfile</i> software. These results reveal a strong dependence of the cation–oxygen and oxygen–oxygen distances on the coordination numbers, which leads to gradients of these distances near the particle surface. The details are dependent on the surface coverage by ligands and adsorbates and on the structure of grain boundaries in nanocrystalline agglomerates. The refined models confirm the expectations of more substantial disorder at particle surfaces, with a distorted surface layer extending over several coordination shells. The results highlight the feasibility of whole-nanoparticle refinements from neutron data, calling for further development of data reduction and analysis procedures.</p>","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":"57 4","pages":"1023-1039"},"PeriodicalIF":5.2000,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Approaches and challenges in whole-nanoparticle refinements from neutron total-scattering data\",\"authors\":\"Bernadette Cladek, Yuanpeng Zhang, Russell Maier, Bruce Ravel, Matthew G. Tucker, Igor Levin\",\"doi\":\"10.1107/S1600576724004321\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>This study considers critical data reduction steps and data analysis approaches required to determine explicitly the atomic arrangements in nanoparticles from time-of-flight neutron total scattering. A practical procedure is described for removing parasitic backgrounds caused by the incoherent scattering of hydrogen inevitably present in most nanoparticle samples and normalizing the recovered coherent scattering intensities onto an absolute scale. A model-free analysis is presented of a pair-distribution function derived from total scattering that can be used to determine thermal expansion coefficients and particle sizes directly from experimental data without knowledge of the material's structure. Finally, atomistic whole-nanoparticle refinements of yttrium-doped ceria nanoparticles from neutron total-scattering data are demonstrated using the reverse Monte Carlo method implemented in the <i>RMCProfile</i> software. These results reveal a strong dependence of the cation–oxygen and oxygen–oxygen distances on the coordination numbers, which leads to gradients of these distances near the particle surface. The details are dependent on the surface coverage by ligands and adsorbates and on the structure of grain boundaries in nanocrystalline agglomerates. The refined models confirm the expectations of more substantial disorder at particle surfaces, with a distorted surface layer extending over several coordination shells. The results highlight the feasibility of whole-nanoparticle refinements from neutron data, calling for further development of data reduction and analysis procedures.</p>\",\"PeriodicalId\":48737,\"journal\":{\"name\":\"Journal of Applied Crystallography\",\"volume\":\"57 4\",\"pages\":\"1023-1039\"},\"PeriodicalIF\":5.2000,\"publicationDate\":\"2024-06-27\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Applied Crystallography\",\"FirstCategoryId\":\"88\",\"ListUrlMain\":\"https://onlinelibrary.wiley.com/doi/10.1107/S1600576724004321\",\"RegionNum\":3,\"RegionCategory\":\"材料科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"CHEMISTRY, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Applied Crystallography","FirstCategoryId":"88","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1107/S1600576724004321","RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
Approaches and challenges in whole-nanoparticle refinements from neutron total-scattering data
This study considers critical data reduction steps and data analysis approaches required to determine explicitly the atomic arrangements in nanoparticles from time-of-flight neutron total scattering. A practical procedure is described for removing parasitic backgrounds caused by the incoherent scattering of hydrogen inevitably present in most nanoparticle samples and normalizing the recovered coherent scattering intensities onto an absolute scale. A model-free analysis is presented of a pair-distribution function derived from total scattering that can be used to determine thermal expansion coefficients and particle sizes directly from experimental data without knowledge of the material's structure. Finally, atomistic whole-nanoparticle refinements of yttrium-doped ceria nanoparticles from neutron total-scattering data are demonstrated using the reverse Monte Carlo method implemented in the RMCProfile software. These results reveal a strong dependence of the cation–oxygen and oxygen–oxygen distances on the coordination numbers, which leads to gradients of these distances near the particle surface. The details are dependent on the surface coverage by ligands and adsorbates and on the structure of grain boundaries in nanocrystalline agglomerates. The refined models confirm the expectations of more substantial disorder at particle surfaces, with a distorted surface layer extending over several coordination shells. The results highlight the feasibility of whole-nanoparticle refinements from neutron data, calling for further development of data reduction and analysis procedures.
期刊介绍:
Many research topics in condensed matter research, materials science and the life sciences make use of crystallographic methods to study crystalline and non-crystalline matter with neutrons, X-rays and electrons. Articles published in the Journal of Applied Crystallography focus on these methods and their use in identifying structural and diffusion-controlled phase transformations, structure-property relationships, structural changes of defects, interfaces and surfaces, etc. Developments of instrumentation and crystallographic apparatus, theory and interpretation, numerical analysis and other related subjects are also covered. The journal is the primary place where crystallographic computer program information is published.