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Napiórkowska E, Szeleszczuk Ł, Milcarz K, Pisklak DM. Density Functional Theory and Density Functional Tight Binding Studies of Thiamine Hydrochloride Hydrates. Molecules 2023; 28:7497. [PMID: 38005219 PMCID: PMC10673443 DOI: 10.3390/molecules28227497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 11/01/2023] [Accepted: 11/07/2023] [Indexed: 11/26/2023] Open
Abstract
Thiamine hydrochloride (THCL), also known as vitamin B1, is an active pharmaceutical ingredient (API), present on the list of essential medicines developed by the WHO, which proves its importance for public health. THCL is highly hygroscopic and can occur in the form of hydrates with varying degrees of hydration, depending on the air humidity. Although experimental characterization of the THCL hydrates has been described in the literature, the questions raised in previously published works suggest that additional research and in-depth analysis of THCL dehydration behavior are still needed. Therefore, the main aim of this study was to characterize, by means of quantum chemical calculations, the behavior of thiamine hydrates and explain the previously obtained results, including changes in the NMR spectra, at the molecular level. To achieve this goal, a series of DFT (CASTEP) and DFTB (DFTB+) calculations under periodic boundary conditions have been performed, including molecular dynamics simulations and GIPAW NMR calculations. The obtained results explain the differences in the relative stability of the studied forms and changes in the spectra observed for the samples of various degrees of hydration. This work highlights the application of periodic DFT calculations in the analysis of various solid forms of APIs.
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Affiliation(s)
- Ewa Napiórkowska
- Department of Organic and Physical Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Banacha 1 Str., 02-093 Warsaw, Poland
- Doctoral School, Medical University of Warsaw, Żwirki i Wigury 81 Str., 02-093 Warsaw, Poland
| | - Łukasz Szeleszczuk
- Department of Organic and Physical Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Banacha 1 Str., 02-093 Warsaw, Poland
| | - Katarzyna Milcarz
- Department of Organic and Physical Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Banacha 1 Str., 02-093 Warsaw, Poland
| | - Dariusz Maciej Pisklak
- Department of Organic and Physical Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Banacha 1 Str., 02-093 Warsaw, Poland
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2
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Su Z, Yang C, Deng Q, Zhou Y, Mao C, Fu Z, Zhu C, Zhang Y. Synthesis of a Novel Spherical-Shell-Structure Polymerized Ionic Liquid Microsphere PILM/Au/Al(OH) 3 Catalyst for Benzyl Alcohol Oxidation. ACS APPLIED MATERIALS & INTERFACES 2023; 15:16631-16639. [PMID: 36943938 DOI: 10.1021/acsami.2c20967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
In order to selectively oxidize benzyl alcohol, a novel noble metal catalyst based on polymer ionic liquids with a core-shell structure was created. First, polymer ionic liquid microspheres (PILMs) were prepared by free radical polymerization. Second, the in situ adsorption of Au nanoparticles on the surface of PILMs was accomplished, thanks to the strong electrostatic interaction between N atoms and metal ions on the diazole ring of PILMs. Additionally, the introduction of Al(OH)3 prevented the aggregation of Au nanoparticles and promoted the catalytic reaction. Finally, the PILM/Au/Al(OH)3 catalyst with a core-shell structure was formed. The effectiveness of the PILM/Au/Al(OH)3 catalyst was assessed by varying the catalyst's type, quantity, amount of Au, amount of H2O2, temperature, and reaction time. After five cycles of experiments, the catalyst was effective and reusable. In addition, the potential catalytic mechanism of the catalyst in the oxidation of benzyl alcohol was proposed.
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Affiliation(s)
- Ziyi Su
- School of Chemistry and Chemical Engineering, Jiangsu Optoelectronic Functional Materials and Engineering Laboratory, Southeast University, Nanjing 211189, P. R. China
| | - Chenghan Yang
- School of Chemistry and Chemical Engineering, Jiangsu Optoelectronic Functional Materials and Engineering Laboratory, Southeast University, Nanjing 211189, P. R. China
| | - Qinghua Deng
- School of Chemistry and Chemical Engineering, Jiangsu Optoelectronic Functional Materials and Engineering Laboratory, Southeast University, Nanjing 211189, P. R. China
| | - Yuming Zhou
- School of Chemistry and Chemical Engineering, Jiangsu Optoelectronic Functional Materials and Engineering Laboratory, Southeast University, Nanjing 211189, P. R. China
| | - Chunfeng Mao
- School of Chemistry and Chemical Engineering, Jiangsu Optoelectronic Functional Materials and Engineering Laboratory, Southeast University, Nanjing 211189, P. R. China
| | - Zhiwei Fu
- Xuzhou B&C Chemical Co. Ltd, Xuzhou 221300, P. R. China
| | - Chenzi Zhu
- School of Chemistry and Chemical Engineering, Jiangsu Optoelectronic Functional Materials and Engineering Laboratory, Southeast University, Nanjing 211189, P. R. China
| | - Yiwei Zhang
- School of Chemistry and Chemical Engineering, Jiangsu Optoelectronic Functional Materials and Engineering Laboratory, Southeast University, Nanjing 211189, P. R. China
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Xu R, Zhou Z, Li J, Zhang X, Zhu Y, Xiao H, Xu L, Ding Y, Li A, Fang G. Reaction mechanism of atomic layer deposition of zirconium oxide using zirconium precursors bearing amino ligands and water. Front Chem 2022; 10:1035902. [PMID: 36405315 PMCID: PMC9672480 DOI: 10.3389/fchem.2022.1035902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 10/06/2022] [Indexed: 11/06/2022] Open
Abstract
As a unique nanofabrication technology, atomic layer deposition (ALD) has been widely used for the preparation of various materials in the fields of microelectronics, energy and catalysis. As a high-κ gate dielectric to replace SiO2, zirconium oxide (ZrO2) has been prepared through the ALD method for microelectronic devices. In this work, through density functional theory calculations, the possible reaction pathways of ZrO2 ALD using tetrakis(dimethylamino)zirconium (TDMAZ) and water as the precursors were explored. The whole ZrO2 ALD reaction could be divided into two sequential reactions, TDMAZ and H2O reactions. In the TDMAZ reaction on the hydroxylated surface, the dimethylamino group of TDMAZ could be directly eliminated by substitution and ligand exchange reactions with the hydroxyl group on the surface to form dimethylamine (HN(CH3)2). In the H2O reaction with the aminated surface, the reaction process is much more complex than the TDMAZ reaction. These reactions mainly include ligand exchange reactions between the dimethylamino group of TDMAZ and H2O and coupling reactions for the formation of the bridged products and the by-product of H2O or HN(CH3)2. These insights into surface reaction mechanism of ZrO2 ALD can provide theoretical guidance for the precursor design and improving ALD preparation of other oxides and zirconium compounds, which are based ALD reaction mechanism.
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Affiliation(s)
- Rui Xu
- Key Laboratory of Carbon Materials of Zhejiang Province, College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, China
| | - Zhongchao Zhou
- Key Laboratory of Carbon Materials of Zhejiang Province, College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, China
| | - Jing Li
- Key Laboratory of Carbon Materials of Zhejiang Province, College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, China
| | - Xu Zhang
- Key Laboratory of Carbon Materials of Zhejiang Province, College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, China
| | - Yuanyuan Zhu
- Key Laboratory of Carbon Materials of Zhejiang Province, College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, China
| | - Hongping Xiao
- Key Laboratory of Carbon Materials of Zhejiang Province, College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, China,*Correspondence: Hongping Xiao, ; Lina Xu, ; Guoyong Fang,
| | - Lina Xu
- Key Laboratory of Carbon Materials of Zhejiang Province, College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, China,*Correspondence: Hongping Xiao, ; Lina Xu, ; Guoyong Fang,
| | - Yihong Ding
- Key Laboratory of Carbon Materials of Zhejiang Province, College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, China
| | - Aidong Li
- National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences, Nanjing University, Nanjing, China
| | - Guoyong Fang
- Key Laboratory of Carbon Materials of Zhejiang Province, College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, China,*Correspondence: Hongping Xiao, ; Lina Xu, ; Guoyong Fang,
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Loukhovitski BI, Pelevkin AV, Sharipov AS. Toward size-dependent thermodynamics of nanoparticles from quantum chemical calculations of small atomic clusters: a case study of (B 2O 3) n. Phys Chem Chem Phys 2022; 24:13130-13148. [PMID: 35587125 DOI: 10.1039/d2cp01672a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present a method for obtaining canonical partition functions and, accordingly, temperature-dependent thermodynamics of arbitrary-sized (nano) particles from electronic structure calculations of the corresponding small size atomic clusters. The guiding idea here is to extrapolate the basic properties underlying the thermochemistry of clusters (electronic energies, rotational constants, and vibrational frequencies) rather than the thermodynamic functions themselves. The thus obtained scaling dependences for these basic properties expressed in a simple analytical form provide an efficient tool for fast evaluation of the size-selected thermochemical data for particles of any nuclearity. To exemplify the performance of the methodology, neutral stoichiometric boron oxide clusters are considered. To this end, the geometry and various physical properties of the energetically lowest-lying (B2O3)n (n = 1,…,8) structures are found using density functional theory and the authors' multistage hierarchical procedure customized for global optimization of quite large cluster structures. With these data and based on the physically consistent scaling regularities for the principal cluster properties, the size-selected thermodynamic functions of boron oxide particles in the gas phase, such as enthalpy, entropy, and specific heat capacity, are derived. The variation of these characteristics with increasing cluster size is discussed in detail as well. To facilitate handling of the temperature and size dependences we have found here in further chemical kinetic and equilibrium modeling, the tabulated thermodynamic functions of interest are fitted for n = 1,…,1000 to the standard seven-parameter Chemkin polynomials.
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Affiliation(s)
- Boris I Loukhovitski
- Central Institute of Aviation Motors, Aviamotornaya 2, Moscow 111116, Russia. .,Joint Institute for High Temperatures of the Russian Academy of Sciences, Izhorskaya 13 Bldg. 2, Moscow 125412, Russia
| | - Alexey V Pelevkin
- Central Institute of Aviation Motors, Aviamotornaya 2, Moscow 111116, Russia. .,Prokhorov General Physics Institute of the Russian Academy of Sciences, Vavilova 38, Moscow 119991, Russia
| | - Alexander S Sharipov
- Central Institute of Aviation Motors, Aviamotornaya 2, Moscow 111116, Russia. .,Joint Institute for High Temperatures of the Russian Academy of Sciences, Izhorskaya 13 Bldg. 2, Moscow 125412, Russia
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Buelna-García CE, Castillo-Quevedo C, Quiroz-Castillo JM, Paredes-Sotelo E, Cortez-Valadez M, Martin-del-Campo-Solis MF, López-Luke T, Utrilla-Vázquez M, Mendoza-Wilson AM, Rodríguez-Kessler PL, Vazquez-Espinal A, Pan S, de Leon-Flores A, Mis-May JR, Rodríguez-Domínguez AR, Martínez-Guajardo G, Cabellos JL. Relative Populations and IR Spectra of Cu 38 Cluster at Finite Temperature Based on DFT and Statistical Thermodynamics Calculations. Front Chem 2022; 10:841964. [PMID: 35300385 PMCID: PMC8921525 DOI: 10.3389/fchem.2022.841964] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 01/24/2022] [Indexed: 11/13/2022] Open
Abstract
The relative populations of Cu38 isomers depend to a great extent on the temperature. Density functional theory and nanothermodynamics can be combined to compute the geometrical optimization of isomers and their spectroscopic properties in an approximate manner. In this article, we investigate entropy-driven isomer distributions of Cu38 clusters and the effect of temperature on their IR spectra. An extensive, systematic global search is performed on the potential and free energy surfaces of Cu38 using a two-stage strategy to identify the lowest-energy structure and its low-energy neighbors. The effects of temperature on the populations and IR spectra are considered via Boltzmann factors. The computed IR spectrum of each isomer is multiplied by its corresponding Boltzmann weight at finite temperature. Then, they are summed together to produce a final temperature-dependent, Boltzmann-weighted spectrum. Our results show that the disordered structure dominates at high temperatures and the overall Boltzmann-weighted spectrum is composed of a mixture of spectra from several individual isomers.
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Affiliation(s)
- Carlos Emiliano Buelna-García
- Departamento de Investigación en Polímeros y Materiales, Universidad de Sonora, Hermosillo, Mexico
- Organización Científica y Tecnológica del Desierto, Hermosillo, Mexico
| | - Cesar Castillo-Quevedo
- Departamento de Fundamentos del Conocimiento, Centro Universitario del Norte, Universidad de Guadalajara, Colotlán, Mexico
| | | | - Edgar Paredes-Sotelo
- Departamento de Investigación en Polímeros y Materiales, Universidad de Sonora, Hermosillo, Mexico
| | - Manuel Cortez-Valadez
- CONACYT-Departamento de Investigación en Física, Universidad de Sonora, Hermosillo, Mexico
| | | | - Tzarara López-Luke
- Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, Morelia, Mexico
| | | | | | - Peter L. Rodríguez-Kessler
- Laboratorio de Química Inorgánica y Materiales Moleculares, Facultad de Ingeniería, Universidad Autonoma de Chile, Santiago, Chile
| | - Alejandro Vazquez-Espinal
- Comput. Theor. Chem. Group Departamento de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Santiago, Chile
| | - Sudip Pan
- Fachbereich Chemie, Philipps-Universität Marburg, Marburg, Germany
| | - Aned de Leon-Flores
- Departamento de Ciencias Químico Biologicas, Universidad de Sonora, Hermosillo, Mexico
| | | | | | - Gerardo Martínez-Guajardo
- Unidad Académica de Ciencias Químicas, Área de Ciencias de la Salud, Universidad Autónoma de Zacatecas, Zacatecas, Mexico
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Bondarenko AA, Vlasova YS, Polynski MV, Ilyushenkova VV, Ananikov VP. Towards determining molecular structure with ESI-MS backed by computational methods: structures of subnanoclusters of Pd and Cu chlorides, ion dynamics in vacuum, and challenges to the methodology. Inorg Chem Front 2022. [DOI: 10.1039/d2qi01098d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Determining most stable structures of sub-nanoscale ionic clusters in ESI-MS spectra with quantum chemical modeling.
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Affiliation(s)
- Anton A. Bondarenko
- Saint Petersburg State University, Universitetsky Prospect 26, Saint Petersburg 198504, Russia
| | - Yulia S. Vlasova
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, Moscow 119991, Russia
- MSU, Faculty of Chemistry, Leninskiye Gory 1-3, Moscow 119991, Russia
| | - Mikhail V. Polynski
- Saint Petersburg State University, Universitetsky Prospect 26, Saint Petersburg 198504, Russia
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, Moscow 119991, Russia
- MSU, Faculty of Chemistry, Leninskiye Gory 1-3, Moscow 119991, Russia
| | - Valentina V. Ilyushenkova
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, Moscow 119991, Russia
| | - Valentine P. Ananikov
- Saint Petersburg State University, Universitetsky Prospect 26, Saint Petersburg 198504, Russia
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, Moscow 119991, Russia
- MSU, Faculty of Chemistry, Leninskiye Gory 1-3, Moscow 119991, Russia
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7
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Effects of Temperature on Enantiomerization Energy and Distribution of Isomers in the Chiral Cu 13 Cluster. Molecules 2021; 26:molecules26185710. [PMID: 34577181 PMCID: PMC8471510 DOI: 10.3390/molecules26185710] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 09/02/2021] [Accepted: 09/17/2021] [Indexed: 11/21/2022] Open
Abstract
In this study, we report the lowest energy structure of bare Cu13 nanoclusters as a pair of enantiomers at room temperature. Moreover, we compute the enantiomerization energy for the interconversion from minus to plus structures in the chiral putative global minimum for temperatures ranging from 20 to 1300 K. Additionally, employing nanothermodynamics, we compute the probabilities of occurrence for each particular isomer as a function of temperature. To achieve that, we explore the free energy surface of the Cu13 cluster, employing a genetic algorithm coupled with density functional theory. Moreover, we discuss the energetic ordering of isomers computed with various density functionals. Based on the computed thermal population, our results show that the chiral putative global minimum strongly dominates at room temperature.
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Anderson ID, Riskowski RA, Ackerson CJ. Observable but Not Isolable: The RhAu 24 (PET) 181+ Nanocluster. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2004078. [PMID: 33174675 DOI: 10.1002/smll.202004078] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/09/2020] [Indexed: 06/11/2023]
Abstract
The synthesis and characterization of RhAu24 (PET)18 (PET = 2-phenylethanethiol) is described. The cluster is cosynthesized with Au25 (PET)18 and rhodium thiolates in a coreduction of RhCl3 , HAuCl4 , and PET. Rapid decomposition of RhAu24 (PET)18 occurs when purified from the other reaction products, precluding the study of isolated cluster. Mixtures containing RhAu24 (PET)18 , Au25 (PET)18 , and rhodium thiolates are therefore characterized. Mass spectrometry, X-ray photoelectron spectroscopy, and chromatography methods suggest a combination of charge-charge and metallophilic interactions among Au25 (PET)181- , rhodium thiolates and RhAu24 (PET)18 resulting in stabilization of RhAu24 (PET)18 . The charge of RhAu24 (PET)18 is assigned as 1+ on the basis of its stoichiometric 1:1 presence with anionic Au25 (PET)18 , and its stability is contextualized within the superatom electron counting rules. This analysis concludes that the Rh atom absorbs one superatomic electron to close its d-shell, giving RhAu24 (PET)181+ a superatomic electron configuration of 1S2 1P4 . Overall, an updated framework for rationalizing open d-shell heterometal dopant electronics in thiolated gold nanoclusters emerges.
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Affiliation(s)
- Ian D Anderson
- Department of Chemistry, Colorado State University, Fort Collins, CO, 80523, USA
| | - Ryan A Riskowski
- Department of Chemistry, Colorado State University, Fort Collins, CO, 80523, USA
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Buelna-García CE, Robles-Chaparro E, Parra-Arellano T, Quiroz-Castillo JM, del-Castillo-Castro T, Martínez-Guajardo G, Castillo-Quevedo C, de-León-Flores A, Anzueto-Sánchez G, Martin-del-Campo-Solis MF, Mendoza-Wilson AM, Vásquez-Espinal A, Cabellos JL. Theoretical Prediction of Structures, Vibrational Circular Dichroism, and Infrared Spectra of Chiral Be 4B 8 Cluster at Different Temperatures. Molecules 2021; 26:3953. [PMID: 34203563 PMCID: PMC8271876 DOI: 10.3390/molecules26133953] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/18/2021] [Accepted: 06/22/2021] [Indexed: 11/16/2022] Open
Abstract
Lowest-energy structures, the distribution of isomers, and their molecular properties depend significantly on geometry and temperature. Total energy computations using DFT methodology are typically carried out at a temperature of zero K; thereby, entropic contributions to the total energy are neglected, even though functional materials work at finite temperatures. In the present study, the probability of the occurrence of one particular Be4B8 isomer at temperature T is estimated by employing Gibbs free energy computed within the framework of quantum statistical mechanics and nanothermodynamics. To identify a list of all possible low-energy chiral and achiral structures, an exhaustive and efficient exploration of the potential/free energy surfaces is carried out using a multi-level multistep global genetic algorithm search coupled with DFT. In addition, we discuss the energetic ordering of structures computed at the DFT level against single-point energy calculations at the CCSD(T) level of theory. The total VCD/IR spectra as a function of temperature are computed using each isomer's probability of occurrence in a Boltzmann-weighted superposition of each isomer's spectrum. Additionally, we present chemical bonding analysis using the adaptive natural density partitioning method in the chiral putative global minimum. The transition state structures and the enantiomer-enantiomer and enantiomer-achiral activation energies as a function of temperature evidence that a change from an endergonic to an exergonic type of reaction occurs at a temperature of 739 K.
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Affiliation(s)
- Carlos Emiliano Buelna-García
- Departamento de Investigación en Polímeros y Materiales, Edificio 3G, Universidad de Sonora, Hermosillo 83000, Sonora, Mexico; (C.E.B.-G.); (J.M.Q.-C.); (T.d.-C.-C.)
- Organización Científica y Tecnológica del Desierto, Hermosillo 83150, Sonora, Mexico
| | - Eduardo Robles-Chaparro
- Departamento de Ciencias Químico Biologicas, Edificio 5A, Universidad de Sonora, Hermosillo 83000, Sonora, Mexico; (E.R.-C.); (T.P.-A.); (A.d.-L.-F.)
| | - Tristan Parra-Arellano
- Departamento de Ciencias Químico Biologicas, Edificio 5A, Universidad de Sonora, Hermosillo 83000, Sonora, Mexico; (E.R.-C.); (T.P.-A.); (A.d.-L.-F.)
| | - Jesus Manuel Quiroz-Castillo
- Departamento de Investigación en Polímeros y Materiales, Edificio 3G, Universidad de Sonora, Hermosillo 83000, Sonora, Mexico; (C.E.B.-G.); (J.M.Q.-C.); (T.d.-C.-C.)
| | - Teresa del-Castillo-Castro
- Departamento de Investigación en Polímeros y Materiales, Edificio 3G, Universidad de Sonora, Hermosillo 83000, Sonora, Mexico; (C.E.B.-G.); (J.M.Q.-C.); (T.d.-C.-C.)
| | - Gerardo Martínez-Guajardo
- Unidad Académica de Ciencias Químicas, Área de Ciencias de la Salud, Universidad Autónomade Zacatecas, Km. 6 Carretera Zacatecas-Guadalajara s/n, Ejido La Escondida C.P., Zacatecas 98160, Zac, Mexico;
| | - Cesar Castillo-Quevedo
- Departamento de Fundamentos del Conocimiento, Centro Universitario del Norte, Universidad de Guadalajara, Carretera Federal No. 23, Km. 191, C.P., Colotlán 46200, Jalisco, Mexico; (C.C.-Q.); (M.F.M.-d.-C.-S.)
| | - Aned de-León-Flores
- Departamento de Ciencias Químico Biologicas, Edificio 5A, Universidad de Sonora, Hermosillo 83000, Sonora, Mexico; (E.R.-C.); (T.P.-A.); (A.d.-L.-F.)
| | | | - Martha Fabiola Martin-del-Campo-Solis
- Departamento de Fundamentos del Conocimiento, Centro Universitario del Norte, Universidad de Guadalajara, Carretera Federal No. 23, Km. 191, C.P., Colotlán 46200, Jalisco, Mexico; (C.C.-Q.); (M.F.M.-d.-C.-S.)
| | - Ana Maria Mendoza-Wilson
- Coordinación de Tecnología de Alimentos de Origen Vegetal, CIAD, A.C., Carretera Gustavo Enrique Astiazarán Rosas, No. 46, Hermosillo 83304, Sonora, Mexico;
| | - Alejandro Vásquez-Espinal
- Computational and Theoretical Chemistry Group Departamento de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Republica 498, Santiago 8370035, Chile;
| | - Jose Luis Cabellos
- Departamento de Investigación en Física, Edificio 3M, Universidad de Sonora, Hermosillo 83000, Sonora, Mexico
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Exploration of Free Energy Surface and Thermal Effects on Relative Population and Infrared Spectrum of the Be 6B 11- Flux-Ional Cluster. MATERIALS 2020; 14:ma14010112. [PMID: 33383889 PMCID: PMC7796227 DOI: 10.3390/ma14010112] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 12/23/2020] [Accepted: 12/24/2020] [Indexed: 02/06/2023]
Abstract
The starting point to understanding cluster properties is the putative global minimum and all the nearby local energy minima; however, locating them is computationally expensive and difficult. The relative populations and spectroscopic properties that are a function of temperature can be approximately computed by employing statistical thermodynamics. Here, we investigate entropy-driven isomers distribution on Be6B11− clusters and the effect of temperature on their infrared spectroscopy and relative populations. We identify the vibration modes possessed by the cluster that significantly contribute to the zero-point energy. A couple of steps are considered for computing the temperature-dependent relative population: First, using a genetic algorithm coupled to density functional theory, we performed an extensive and systematic exploration of the potential/free energy surface of Be6B11− clusters to locate the putative global minimum and elucidate the low-energy structures. Second, the relative populations’ temperature effects are determined by considering the thermodynamic properties and Boltzmann factors. The temperature-dependent relative populations show that the entropies and temperature are essential for determining the global minimum. We compute the temperature-dependent total infrared spectra employing the Boltzmann factor weighted sums of each isomer’s infrared spectrum and find that at finite temperature, the total infrared spectrum is composed of an admixture of infrared spectra that corresponds to the spectra of the lowest-energy structure and its isomers located at higher energies. The methodology and results describe the thermal effects in the relative population and the infrared spectra.
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12
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Zhu B, Ehara M, Sakaki S. Propene oxidation catalysis and electronic structure of M 55 particles (M = Pd or Rh): differences and similarities between Pd 55 and Rh 55. Phys Chem Chem Phys 2020; 22:11783-11796. [PMID: 32215421 DOI: 10.1039/d0cp00169d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Propene oxidation is one of the important reactions that occurs in the presence of a three-way catalyst but its reaction mechanism is unclear. The reaction mechanisms and differences in catalysis between Pd and Rh particles were investigated by DFT calculations employing Pd55 and Rh55 as the model catalysts. The O-attack mechanism, in which the O atom adsorbed on the Pd55 and Rh55 surfaces attacks the C[double bond, length as m-dash]C double bond of propene, needs to overcome a large activation barrier (Ea). On the other hand, C-H bond cleavage of the methyl group of propene easily occurs with moderate Ea; the mechanism initiated by this C-H activation is named H-transfer mechanism. In this mechanism, the next step is allyl alcohol formation, followed by the second C-H bond activation of the CH2OH species of allyl alcohol, and the final step is proton transfer from OH-substituted π-allyl species to the OH group on the metal surface to yield acrolein and water molecules with the regeneration of M55. The rate-determining step is the second C-H bond activation. Its Ea is 17.4 kcal mol-1 for the reaction on Pd55 and 34.4 kcal mol-1 for the reaction on Rh55. These results indicate that Pd particles are more active than Rh particles in propene oxidation, which agrees with the experimental findings. The larger Ea for Rh55 than that for Pd55 arises from the stronger Rh-OH bond than the Pd-OH bond. The higher energy d-valence band-top of Rh55 than that of Pd55 is the origin of the stronger Rh-OH bond than the Pd-OH bond. Thus, the d-valence band-top energy is an important property for understanding and designing catalysts for alkene oxidation.
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Affiliation(s)
- Bo Zhu
- Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, 1-30 Goryo-Ohara, Nishikyo-ku, Kyoto 615-8245, Japan.
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Gavriil V, Chatzichristidi M, Christofilos D, Kourouklis GA, Kollia Z, Bakalis E, Cefalas AC, Sarantopoulou E. Entropy and Random Walk Trails Water Confinement and Non-Thermal Equilibrium in Photon-Induced Nanocavities. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E1101. [PMID: 32498312 PMCID: PMC7353189 DOI: 10.3390/nano10061101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/18/2020] [Accepted: 05/22/2020] [Indexed: 01/18/2023]
Abstract
Molecules near surfaces are regularly trapped in small cavitations. Molecular confinement, especially water confinement, shows intriguing and unexpected behavior including surface entropy adjustment; nevertheless, observations of entropic variation during molecular confinement are scarce. An experimental assessment of the correlation between surface strain and entropy during molecular confinement in tiny crevices is difficult because strain variances fall in the nanometer scale. In this work, entropic variations during water confinement in 2D nano/micro cavitations were observed. Experimental results and random walk simulations of water molecules inside different size nanocavitations show that the mean escaping time of molecular water from nanocavities largely deviates from the mean collision time of water molecules near surfaces, crafted by 157 nm vacuum ultraviolet laser light on polyacrylamide matrixes. The mean escape time distribution of a few molecules indicates a non-thermal equilibrium state inside the cavity. The time differentiation inside and outside nanocavities reveals an additional state of ordered arrangements between nanocavities and molecular water ensembles of fixed molecular length near the surface. The configured number of microstates correctly counts for the experimental surface entropy deviation during molecular water confinement. The methodology has the potential to identify confined water molecules in nanocavities with life science importance.
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Affiliation(s)
- Vassilios Gavriil
- National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vassileos Constantinou Avenue, 11635 Athens, Greece; (V.G.); (Z.K.); (E.B.); (A.-C.C.)
- School of Chemical Engineering and Physics Laboratory, Faculty of Engineering, Aristotle University of Thessaloniki, University Campus, 54124 Thessaloniki, Greece; (D.C.); (G.A.K.)
| | - Margarita Chatzichristidi
- Department of Chemistry, Laboratory of Industrial Chemistry, Panepistimiopolis Zografou, National and Kapodistrian University of Athens, 15771 Athens, Greece;
| | - Dimitrios Christofilos
- School of Chemical Engineering and Physics Laboratory, Faculty of Engineering, Aristotle University of Thessaloniki, University Campus, 54124 Thessaloniki, Greece; (D.C.); (G.A.K.)
| | - Gerasimos A. Kourouklis
- School of Chemical Engineering and Physics Laboratory, Faculty of Engineering, Aristotle University of Thessaloniki, University Campus, 54124 Thessaloniki, Greece; (D.C.); (G.A.K.)
| | - Zoe Kollia
- National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vassileos Constantinou Avenue, 11635 Athens, Greece; (V.G.); (Z.K.); (E.B.); (A.-C.C.)
| | - Evangelos Bakalis
- National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vassileos Constantinou Avenue, 11635 Athens, Greece; (V.G.); (Z.K.); (E.B.); (A.-C.C.)
- Dipartimento di Chimica “G. Giamician” University di Bologna, Via F. Selmi 2, 40126 Bologna, Italy
| | - Alkiviadis-Constantinos Cefalas
- National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vassileos Constantinou Avenue, 11635 Athens, Greece; (V.G.); (Z.K.); (E.B.); (A.-C.C.)
| | - Evangelia Sarantopoulou
- National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vassileos Constantinou Avenue, 11635 Athens, Greece; (V.G.); (Z.K.); (E.B.); (A.-C.C.)
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14
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Wu Y, Zhang Y, Lv X, Mao C, Zhou Y, Wu W, Zhang H, Huang Z. Synthesis of polymeric ionic liquids mircrospheres/Pd nanoparticles/CeO2 core-shell structure catalyst for catalytic oxidation of benzyl alcohol. J Taiwan Inst Chem Eng 2020. [DOI: 10.1016/j.jtice.2019.11.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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15
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Kauppinen MM, Melander MM, Honkala K. First-principles insight into CO hindered agglomeration of Rh and Pt single atoms on m-ZrO 2. Catal Sci Technol 2020. [DOI: 10.1039/d0cy00413h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Kinetic and thermodynamic stability of single-atom and nanocluster catalysts is addressed under reaction conditions within a DFT-parametrised multi-scale thermodynamic framework combining atomistic, non-equilibrium, and nanothermodynamics.
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Affiliation(s)
| | - Marko M. Melander
- Department of Chemistry
- Nanoscience Center
- University of Jyväskylä
- Finland
| | - Karoliina Honkala
- Department of Chemistry
- Nanoscience Center
- University of Jyväskylä
- Finland
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16
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Sharipov AS, Loukhovitski BI. Small atomic clusters: quantum chemical research of isomeric composition and physical properties. Struct Chem 2019. [DOI: 10.1007/s11224-019-01417-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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17
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Mendoza-Pérez R, Guisbiers G. Bimetallic Pt-Pd nano-catalyst: size, shape and composition matter. NANOTECHNOLOGY 2019; 30:305702. [PMID: 30965294 DOI: 10.1088/1361-6528/ab1759] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The goal of this work is to understand how the phase diagram (PHAD) of the platinum-palladium (Pt-Pd) alloy changes with size and shape and how it correlates with catalytic properties. By using nano-thermodynamics, the size and shape effects on the PHAD of Pt-Pd nanoparticles were determined theoretically. The PHAD of some nanoparticles (sphere, tetrahedron, octahedron, decahedron, cube, cuboctahedron and rhombic dodecahedron) exhibits a congruent melting point that becomes more and more pronounced when the size decreases. At the right of the congruent melting point i.e. close to the Pt-rich side, the coexistence region exhibits a contraction while an expansion is noticed at larger palladium concentrations. From the Gibbs free energy analysis, the stability of all the considered shapes has been determined versus temperature and composition. Furthermore, the surface segregation was also calculated and it is shown that the surface segregation is reversed at very small sizes. Indeed, below a critical size, Pd does not segregate anymore at the surface like it normally does for larger nanoparticles; but Pt does. The critical size range has been determined for each considered shape; and within this range Pt and Pd co-exist at the surface. Finally, the most catalytically active shapes are predicted to be the tetrahedron and the cube in agreement with the available experimental data and other theoretical results.
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Affiliation(s)
- Rafael Mendoza-Pérez
- Instituto de Investigaciones en Materiales, UNAM, Circuito Exterior s/n, Ciudad Universitaria, Coyoacán, 04510 CDMX, México
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18
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Baletto F. Structural properties of sub-nanometer metallic clusters. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:113001. [PMID: 30562724 DOI: 10.1088/1361-648x/aaf989] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
At the nanoscale, the investigation of structural features becomes fundamental as we can establish relationships between cluster geometries and their physicochemical properties. The peculiarity lies in the variety of shapes often unusual and far from any geometrical and crystallographic intuition clusters can assume. In this respect, we should treat and consider nanoparticles as a new form of matter. Nanoparticle structures depend on their size, chemical composition, ordering, as well as external conditions e.g. synthesis method, pressure, temperature, support. On top of that, at finite temperatures nanoparticles can fluctuate among different structures, opening new and exciting horizons for the design of optimal nanoparticles for advanced applications. This article aims to overview geometrical features of transition metal clusters and of their various rearrangements.
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Affiliation(s)
- Francesca Baletto
- Physics Department, King's College London, WC2R 2LS, London, United Kingdom
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19
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Grigoryan VG, Springborg M. Temperature and isomeric effects in nanoclusters. Phys Chem Chem Phys 2019; 21:5646-5654. [PMID: 30793128 DOI: 10.1039/c9cp00123a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The canonical thermodynamics of clusters is determined quantum mechanically in the general case of multiple minima of the potential energy surface (PES) using the superposition approximation. As an illustration of the consequences of our approach, we study in detail the thermodynamic properties of CuN clusters with N from 2 to 150 as a function of cluster size, temperature, and number of isomers. Thereby, for instance, solid-solid transition temperatures for several cluster sizes are determined. We show that the cluster vibrations have a strong impact on the stability of the clusters and that this can be observed not only at medium and high temperatures but also at low temperatures and even at T = 0 K. Thus, including zero-point corrections can change the relative energetic ordering of different isomers. This isomeric effect results in an oscillatory dependence of the heat capacity on cluster size at moderate and high temperatures. Moreover, for the identification of magic clusters at non-vanishing temperature, the Helmholtz free energy is analyzed as a function of cluster size and temperature within a one-, two-, and three-minima model of the PES. Thereby, we demonstrate that the concept of magic clusters is strongly temperature dependent so that in several cases clusters change from being magic or non-magic at T = 0 K to be the opposite at non-vanishing temperature. We emphasize that all these effects are not specific for copper clusters alone but can also be observed in other metal or semiconductor nanoclusters.
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Affiliation(s)
- Valeri G Grigoryan
- Physical and Theoretical Chemistry, University of Saarland, 66123, Saarbrücken, Germany.
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20
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Jindal S, Bulusu SS. A transferable artificial neural network model for atomic forces in nanoparticles. J Chem Phys 2018; 149:194101. [DOI: 10.1063/1.5043247] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Shweta Jindal
- Discipline of Chemistry, Indian Institute of Technology Indore, Simrol, Indore 453552, India
| | - Satya S. Bulusu
- Discipline of Chemistry, Indian Institute of Technology Indore, Simrol, Indore 453552, India
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21
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Ashrafizadeh S. Thermodynamic paths for calculating energy balance in systems containing nanoparticles. Chem Phys Lett 2018. [DOI: 10.1016/j.cplett.2018.05.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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22
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23
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Photons Probe Entropic Potential Variation during Molecular Confinement in Nanocavities. ENTROPY 2018; 20:e20080545. [PMID: 33265634 PMCID: PMC7513070 DOI: 10.3390/e20080545] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 07/20/2018] [Accepted: 07/21/2018] [Indexed: 12/02/2022]
Abstract
In thin polymeric layers, external molecular analytes may well be confined within tiny surface nano/microcavities, or they may be attached to ligand adhesion binding sites via electrical dipole forces. Even though molecular trapping is followed by a variation of the entropic potential, the experimental evidence of entropic energy variation from molecular confinement is scarce because tiny thermodynamic energy density diverseness can be tracked only by sub-nm surface strain. Here, it is shown that water confinement within photon-induced nanocavities in Poly (2-hydroxyethyl methacrylate), (PHEMA) layers could be trailed by an entropic potential variation that competes with a thermodynamic potential from electric dipole attachment of molecular adsorbates in polymeric ligands. The nano/microcavities and the ligands were fabricated on a PHEMA matrix by vacuum ultraviolet laser photons at 157 nm. The entropic energy variation during confinement of water analytes on the photon processed PHEMA layer was monitored via sub-nm surface strain by applying white light reflectance spectroscopy, nanoindentation, contact angle measurements, Atomic Force Microscopy (AFM) imaging, and surface and fractal analysis. The methodology has the potency to identify entropic energy density variations less than 1 pJm−3 and to monitor dipole and entropic fields on biosurfaces.
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24
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Elucidation of the molecular and electronic structures of some magic silver clusters Ag n (n = 8, 18, 20). J Mol Model 2018; 24:209. [PMID: 30022315 DOI: 10.1007/s00894-018-3730-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 06/19/2018] [Indexed: 01/08/2023]
Abstract
Density functional theory (DFT) calculations were carried out to explore the geometric, spectroscopic, and electronic properties of three magic silver clusters Agn (n = 8, 18, and 20) in detail. The computed results show that the global minima of these clusters are compact, near-spherical structures, while other low-lying isomers exhibit oblate or prolate shapes. Vertical ionization energies for the low-lying isomers were also computed and assigned with respect to available experimental values. Although several isomers were predicted to have similar energies, their electronic and vibrational signatures were quite distinctive, meaning that they could be used as fingerprint signals to distinguish between isomers. In addition, the electronic structures of these systems were explored using the phenomenological shell model. Calculations for the coinage metal clusters M20 (M = Cu, Ag, Au) indicated that the structures and properties of the Ag cluster are similar to those of the Cu cluster in that both Cu20 and Ag20 prefer a compact structure whereas Au20 prefers to adopt a tetrahedral form. Graphical abstract Shell Orbitals of Ag8 Cluster.
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25
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Rossi K, Pártay LB, Csányi G, Baletto F. Thermodynamics of CuPt nanoalloys. Sci Rep 2018; 8:9150. [PMID: 29904180 PMCID: PMC6002547 DOI: 10.1038/s41598-018-27308-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 05/17/2018] [Indexed: 11/17/2022] Open
Abstract
The control of structural and chemical transitions in bimetallic nanoalloys at finite temperatures is one of the challenges for their use in advanced applications. Comparing Nested Sampling and Molecular Dynamics simulations, we investigate the phase changes of CuPt nanoalloys with the aim to elucidate the role of kinetic effects during their solidification and melting processes. We find that the quasi-thermodynamic limit for the nucleation of (CuPt)309 is 965 ± 10 K, but its prediction is increasingly underestimated when the system is cooled faster than 109 K/s. The solidified nanoparticles, classified following a novel tool based on Steinhardt parameters and the relative orientation of characteristic atomic environments, are then heated back to their liquid phase. We demonstrate the kinetic origin of the hysteresis in the caloric curve as (i) it closes for rates slower than 108 K/s, with a phase change temperature of 970 K ± 25 K, in very good agreement with its quasi-thermodynamic limit; (ii) the process happens simultaneously in the inner and outer layers; (iii) an onion-shell chemical order - Cu-rich surface, Pt-rich sub-surface, and mixed core - is always preserved.
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Affiliation(s)
- K Rossi
- Physics Department, King's College London, London, WC2R 2LS, United Kingdom
| | - L B Pártay
- Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, United Kingdom.,Department of Chemistry, University of Reading, Whiteknights, Reading, RG6 6AD, United Kingdom
| | - G Csányi
- Engineering Department, University of Cambridge, Cambridge, CB2 1PZ, United Kingdom
| | - F Baletto
- Physics Department, King's College London, London, WC2R 2LS, United Kingdom.
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26
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Chiriki S, Jindal S, Bulusu SS. Neural network potentials for dynamics and thermodynamics of gold nanoparticles. J Chem Phys 2018; 146:084314. [PMID: 28249420 DOI: 10.1063/1.4977050] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
For understanding the dynamical and thermodynamical properties of metal nanoparticles, one has to go beyond static and structural predictions of a nanoparticle. Accurate description of dynamical properties may be computationally intensive depending on the size of nanoparticle. Herein, we demonstrate the use of atomistic neural network potentials, obtained by fitting quantum mechanical data, for extensive molecular dynamics simulations of gold nanoparticles. The fitted potential was tested by performing global optimizations of size selected gold nanoparticles (Aun, 17 ≤ n ≤ 58). We performed molecular dynamics simulations in canonical (NVT) and microcanonical (NVE) ensembles on Au17, Au34, Au58 for a total simulation time of around 3 ns for each nanoparticle. Our study based on both NVT and NVE ensembles indicate that there is a dynamical coexistence of solid-like and liquid-like phases near melting transition. We estimate the probability at finite temperatures for set of isomers lying below 0.5 eV from the global minimum structure. In the case of Au17 and Au58, the properties can be estimated using global minimum structure at room temperature, while for Au34, global minimum structure is not a dominant structure even at low temperatures.
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Affiliation(s)
- Siva Chiriki
- Discipline of Chemistry, Indian Institute of Technology (IIT) Indore, Madhya Pradesh 453552, India
| | - Shweta Jindal
- Discipline of Chemistry, Indian Institute of Technology (IIT) Indore, Madhya Pradesh 453552, India
| | - Satya S Bulusu
- Discipline of Chemistry, Indian Institute of Technology (IIT) Indore, Madhya Pradesh 453552, India
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27
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Sun G, Sautet P. Metastable Structures in Cluster Catalysis from First-Principles: Structural Ensemble in Reaction Conditions and Metastability Triggered Reactivity. J Am Chem Soc 2018; 140:2812-2820. [PMID: 29424224 DOI: 10.1021/jacs.7b11239] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Reactivity studies on catalytic transition metal clusters are usually performed on a single global minimum structure. With the example of a Pt13 cluster under a pressure of hydrogen, we show from first-principle calculations that low energy metastable structures of the cluster can play a major role for catalytic reactivity and that hence consideration of the global minimum structure alone can severely underestimate the activity. The catalyst is fluxional with an ensemble of metastable structures energetically accessible at reaction conditions. A modified genetic algorithm is proposed to comprehensively search for the low energy metastable ensemble (LEME) structures instead of merely the global minimum structure. In order to reduce the computational cost of density functional calculations, a high dimensional neural network potential is employed to accelerate the exploration. The presence and influence of LEME structures during catalysis is discussed by the example of H covered Pt13 clusters for two reactions of major importance: hydrogen evolution reaction and methane activation. The results demonstrate that although the number of accessible metastable structures is reduced under reaction condition for Pt13 clusters, these metastable structures can exhibit high activity and dominate the observed activity due to their unique electronic or structural properties. This underlines the necessity of thoroughly exploring the LEME structures in catalysis simulations. The approach enables one to systematically address the impact of isomers in catalysis studies, taking into account the high adsorbate coverage induced by reaction conditions.
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Affiliation(s)
- Geng Sun
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles , Los Angeles, California 90095, United States
| | - Philippe Sautet
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles , Los Angeles, California 90095, United States.,Department of Chemistry and Biochemistry, University of California, Los Angeles , Los Angeles, California 90095, United States
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28
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Loukhovitski BI, Torokhov SA, Loukhovitskaya EE, Sharipov AS. DFT study of small aluminum and boron hydrides: isomeric composition and physical properties. Struct Chem 2018. [DOI: 10.1007/s11224-017-1000-5 https:/doi.org/10.1007/s11224-017-1000-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
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29
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Divi S, Chatterjee A. Generalized nano-thermodynamic model for capturing size-dependent surface segregation in multi-metal alloy nanoparticles. RSC Adv 2018; 8:10409-10424. [PMID: 35547658 PMCID: PMC9087905 DOI: 10.1039/c8ra00945g] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 03/06/2018] [Indexed: 12/13/2022] Open
Abstract
Multi-metal alloy nanoparticles (NPs) offer new avenues for exploration and design of nanoscale-properties, e.g., catalytic, electronic and optical properties, by virtue of their tunable composition. A method that can aid such exploration by accurately predicting the size-, shape- and composition-dependent elemental distribution associated with nanomaterials is crucially missing. A nano-thermodynamic model based on distribution coefficients Δ is introduced to fill this gap. Δ is employed to predict surface segregation in NPs as a function of the NP size and composition. Interestingly, we find Δ to be independent of size for NPs beyond 2 nm. This key finding motivates the construction of thermodynamic tables for distribution coefficients using segregation observed with one or more NP sizes. The tables can enable accurate prediction of phase diagrams for nanomaterials across a wide-range of sizes. Key concepts of this new theory are demonstrated with Au–Pt–Pd, Ag–Au–Pd and Ni–Pt–Pd, which are found to exhibit complex size-dependent segregation behavior for 2–6 nm NPs and relatively weaker size-dependence beyond 6 nm. Numerically well-converged values of Δ are calculated for small NPs using Monte Carlo simulations in the canonical ensemble. Simulations are based on an embedded atom method (EAM) potential for metal alloys. Nano-thermodynamic model captures thermodynamic preference of metal species for different regions of a nanoparticle while accounting for size effects.![]()
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Affiliation(s)
- Srikanth Divi
- Department of Chemical Engineering
- Indian Institute of Technology Bombay
- Mumbai
- India – 400076
| | - Abhijit Chatterjee
- Department of Chemical Engineering
- Indian Institute of Technology Bombay
- Mumbai
- India – 400076
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30
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Loukhovitski BI, Sharipov AS, Starik AM. Quantum chemical study of small Al n B m clusters: Structure and physical properties. Chem Phys 2017. [DOI: 10.1016/j.chemphys.2017.06.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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31
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DFT study of small aluminum and boron hydrides: isomeric composition and physical properties. Struct Chem 2017. [DOI: 10.1007/s11224-017-1000-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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32
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33
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Jindal S, Chiriki S, Bulusu SS. Spherical harmonics based descriptor for neural network potentials: Structure and dynamics of Au 147 nanocluster. J Chem Phys 2017; 146:204301. [PMID: 28571343 PMCID: PMC5440236 DOI: 10.1063/1.4983392] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 04/28/2017] [Indexed: 01/09/2023] Open
Abstract
We propose a highly efficient method for fitting the potential energy surface of a nanocluster using a spherical harmonics based descriptor integrated with an artificial neural network. Our method achieves the accuracy of quantum mechanics and speed of empirical potentials. For large sized gold clusters (Au147), the computational time for accurate calculation of energy and forces is about 1.7 s, which is faster by several orders of magnitude compared to density functional theory (DFT). This method is used to perform the global minimum optimizations and molecular dynamics simulations for Au147, and it is found that its global minimum is not an icosahedron. The isomer that can be regarded as the global minimum is found to be 4 eV lower in energy than the icosahedron and is confirmed from DFT. The geometry of the obtained global minimum contains 105 atoms on the surface and 42 atoms in the core. A brief study on the fluxionality in Au147 is performed, and it is concluded that Au147 has a dynamic surface, thus opening a new window for studying its reaction dynamics.
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Affiliation(s)
- Shweta Jindal
- Discipline of Chemistry, Indian Institute of Technology (IIT), Simrol, Indore, Madhya Pradesh 453552, India
| | - Siva Chiriki
- Discipline of Chemistry, Indian Institute of Technology (IIT), Simrol, Indore, Madhya Pradesh 453552, India
| | - Satya S Bulusu
- Discipline of Chemistry, Indian Institute of Technology (IIT), Simrol, Indore, Madhya Pradesh 453552, India
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34
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Cui M, Lu H, Jiang H, Cao Z, Meng X. Phase Diagram of Continuous Binary Nanoalloys: Size, Shape, and Segregation Effects. Sci Rep 2017; 7:41990. [PMID: 28169320 PMCID: PMC5294570 DOI: 10.1038/srep41990] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 01/04/2017] [Indexed: 12/03/2022] Open
Abstract
The phase diagrams of continuous binary nanoalloys are important in providing guidance for material designs and industrial applications. However, experimental determination of the nano-phase diagram is scarce since calorimetric measurements remain quite challenging at the nanoscale. Based on the size-dependent cohesive energy model, we developed a unified nano-thermodynamic model to investigate the effects of the size, shape, and segregation on the phase diagrams of continuous binary nanoalloys. The liquidus/solidus dropped in temperature, two-phase zone was narrowed, and the degree of surface segregation decreased with decrease in the size or increase in the shape factor. The congruent melting point of Cu-Au nanoalloys with and without segregation is linearly shifted to higher Au component and lower temperature with decreasing size or increasing shape factor. By reviewing surface segregated element of different binary nanoalloys, two segregation rules based on the solid surface energy and atomic size have been identified. Moreover, the established model can be employed to describe other physicochemical properties of nanoalloys, e.g. the cohesive energy, catalytic activation energy, and order-disorder transition temperature, and the validity is supported by available other theoretical prediction, experimental data and molecular dynamic simulations results. This will help the experimentalists by guiding them in their attempts to design bimetallic nanocrystals with the desired properties.
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Affiliation(s)
- Mingjin Cui
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, College of Engineering and Applied Sciences, Institute of Materials Engineering, Nanjing University, Jiangsu, PR China
| | - Haiming Lu
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, College of Engineering and Applied Sciences, Institute of Materials Engineering, Nanjing University, Jiangsu, PR China
| | - Haiping Jiang
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, College of Engineering and Applied Sciences, Institute of Materials Engineering, Nanjing University, Jiangsu, PR China
| | - Zhenhua Cao
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, College of Engineering and Applied Sciences, Institute of Materials Engineering, Nanjing University, Jiangsu, PR China
| | - Xiangkang Meng
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, College of Engineering and Applied Sciences, Institute of Materials Engineering, Nanjing University, Jiangsu, PR China
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35
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Naveenraj S, Mangalaraja RV, Wu JJ, Asiri AM, Anandan S. Gold Triangular Nanoprisms and Nanodecahedra: Synthesis and Interaction Studies with Luminol toward Biosensor Applications. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:11854-11860. [PMID: 27775363 DOI: 10.1021/acs.langmuir.6b02976] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Gold triangular nanoprisms and nanodecahedra (pentagonal bipyramids) were synthesized in the absence and presence of nanoseeds by a simple solvothermal synthesis through the reduction of Auric Chloride (HAuCl4) with poly(vinylpyrrolidone) (PVP) in N,N-dimethylformamide (DMF), respectively. These gold nanoparticles exhibit two plasmon resonance bands. The interaction of these gold nanoparticles with luminol was investigated using UV-vis and fluorescence spectroscopy since hefty number of environmental and biological sensors are based on the combination of luminol and gold nanoparticles. The gold nanoparticles quenches the fluorescence of luminol through a static quenching mechanism, i.e., ground state complex formation, which was confirmed by both absorption spectroscopy as well as time-resolved fluorescence spectroscopy. The Stern-Volmer quenching constant and the effective quenching constant determine that gold nanodecahedra has more interaction with luminol than that of triangular gold nanoprisms. The distance between the gold nanoparticles and luminol, calculated using FRET theory, is less than 8 nm, which indicates efficient energy transfer during interaction. These results are expected to be useful for the development of novel sensors.
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Affiliation(s)
- Selvaraj Naveenraj
- Nanomaterials & Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology , Tiruchirappalli 620015, India
- Advanced Ceramics and Nanotechnology Laboratory, Department of Materials Engineering, University of Concepcion , Concepcion, Chile
| | | | - Jerry J Wu
- Department of Environmental Engineering and Science, Feng Chia University , Taichung 407, Taiwan
| | - Abdullah M Asiri
- The Center of Excellence for Advanced Materials Research, King Abdulaziz University , P.O. Box 80203, Jeddah 21413, Saudi Arabia
| | - Sambandam Anandan
- Nanomaterials & Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology , Tiruchirappalli 620015, India
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36
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Abstract
Conventional thermodynamics for bulk substances encounters challenges when one considers materials on the nanometer scale. Quantities such as entropy, enthalpy, free energy, melting temperature, ordering temperature, Debye temperature, and specific heat no longer remain constant but change with the crystal dimension, size, and morphology. Often, one phenomenon is associated with a variety of theories from different perspectives. Still, a model that can reconcile the size and shape dependence of the thermal properties of the nanoscaled substances remains one of the goals of nanoscience and nanotechnology. This Account highlights the nanoscopic thermodynamics for nanoparticles, nanowires, and nanofilms, with particular emphasis on the bond energy model. The central idea is that the atomic cohesive energy determines the thermodynamic performance of a substance and the cohesive energy varies with the atomic coordination environment. It is the cohesive energy difference between the core and the shell that dictates the nanoscopic thermodynamics. This bond energy model rationalizes the following: (i) how the surface dangling bonds depress the melting temperature, entropy, and enthalpy; (ii) how the order-disorder transition of the nanoparticles depends on particle size and how their stability may vary when they are embedded in an appropriate matrix; (iii) predictions of the existence of face-centered cubic structures of Ti, Zr, and Hf at small size; (iv) how two elements that are immiscible in the bulk can form an alloy on the nanoscale, where the critical size can be predicted. The model has enabled us to reproduce the size and shape dependence of a number of physical properties, such as melting temperature, melting entropy, melting enthalpy, ordering temperature, Gibbs free energy, and formation heat, among others, for materials such as Pd, Au, Ag, Cu, Ni, Sn, Pb, In, Bi, Al, Ti, Zr, Hf, In-Al, Ag-Ni, Co-Pt, Cu-Ag, Cu-Ni, Au-Ni, Ag-Pt, and Au-Pt on the nanometer scale. Furthermore, this model predicts the phenomena of the thermal stability of metal particles on graphene, the superheating of embedded nanoparticles, the order-disorder transition of nanoalloys, the size-temperature phase diagram for low-dimensional solids and the alloying ability on the nanoscale. Extensions of this model may lead to the design of new functional nanomaterials.
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Affiliation(s)
- Weihong Qi
- School of Materials Science and Engineering, Central South University, Changsha, Hunan 410083, China
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Politano A, Cupolillo A, Di Profio G, Arafat HA, Chiarello G, Curcio E. When plasmonics meets membrane technology. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:363003. [PMID: 27414212 DOI: 10.1088/0953-8984/28/36/363003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In this review, we present the applications of thermoplasmonics in membrane processes. We discuss the influence of the heat capacity of the solvent, the amount of plasmonic nanoparticles in the membrane, the intensity of the light source and the transmembrane flow rate on the increase of permeability. Remarkably, thermoplasmonic effects do not involve any noticeable loss of membrane rejection. Herein, we consider application feasibilities, including application fields, requirements of feed, alternatives of light sources, promising thermoplasmonic nanoparticles and scaling up issues.
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Affiliation(s)
- A Politano
- Department of Physics, University of Calabria, Via P. Bucci cubo 31/C, 87036 Rende (CS), Italy
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38
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Thermoplasmonic Study of a Triple Band Optical Nanoantenna Strongly Coupled to Mid IR Molecular Mode. Sci Rep 2016; 6:22227. [PMID: 26916549 PMCID: PMC4768094 DOI: 10.1038/srep22227] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 02/04/2016] [Indexed: 01/21/2023] Open
Abstract
We report the first thermal study of a triple band plasmonic nanoantenna strongly coupled to a molecular mode at mid IR wavelength (MW IR). The hybrid plasmonic structure supports three spatially and spectrally variant resonances of which two are magnetic and one is dipolar in nature. A hybridized mode is excited by coupling the structure’s plasmonic mode with the vibrational mode of PMMA at 5.79 μm. Qualitative agreement between the spectral changes in simulation and experiment clearly indicates that resistive heating is the dominant mechanisms behind the intensity changes of the dipolar and magnetic peaks. The study also unveils the thermal insensitivity of the coupled mode intensity as the temperature is increased. We propose a mechanism to reduce the relative intensity change of the coupled mode at elevated temperature by mode detuning and surface current engineering and demonstrate less than 9% intensity variation. Later, we perform a temperature cycling test and investigate into the degradation of the Au-PMMA composite device. The failure condition is identified to be primarily associated with the surface chemistry of the material interface rather than the deformation of the nanopatterns. The study reveals the robustness of the strongly coupled hybridized mode even under multiple cycling.
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39
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Guisbiers G, Mendoza-Cruz R, Bazán-Díaz L, Velázquez-Salazar JJ, Mendoza-Perez R, Robledo-Torres JA, Rodriguez-Lopez JL, Montejano-Carrizales JM, Whetten RL, José-Yacamán M. Electrum, the Gold-Silver Alloy, from the Bulk Scale to the Nanoscale: Synthesis, Properties, and Segregation Rules. ACS NANO 2016; 10:188-98. [PMID: 26605557 PMCID: PMC4734609 DOI: 10.1021/acsnano.5b05755] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 11/20/2015] [Indexed: 05/26/2023]
Abstract
The alloy Au-Ag system is an important noble bimetallic phase, both historically (as "Electrum") and now especially in nanotechnology, as it is applied in catalysis and nanomedicine. To comprehend the structural characteristics and the thermodynamic stability of this alloy, a knowledge of its phase diagram is required that considers explicitly its size and shape (morphology) dependence. However, as the experimental determination remains quite challenging at the nanoscale, theoretical guidance can provide significant advantages. Using a regular solution model within a nanothermodynamic approach to evaluate the size effect on all the parameters (melting temperature, melting enthalpy, and interaction parameters in both phases), the nanophase diagram is predicted. Besides an overall shift downward, there is a "tilting" effect on the solidus-liquidus curves for some particular shapes exposing the (100) and (110) facets (cube, rhombic dodecahedron, and cuboctahedron). The segregation calculation reveals the preferential presence of silver at the surface for all the polyhedral shapes considered, in excellent agreement with the latest transmission electron microscopy observations and energy dispersive spectroscopy analysis. By reviewing the nature of the surface segregated element of different bimetallic nanoalloys, two surface segregation rules, based on the melting temperatures and surface energies, are deduced. Finally, the optical properties of Au-Ag nanoparticles, calculated within the discrete dipole approximation, show the control that can be achieved in the tuning of the local surface plasmon resonance, depending of the alloy content, the chemical ordering, the morphology, the size of the nanoparticle, and the nature of the surrounding environment.
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Affiliation(s)
- Grégory Guisbiers
- Department
of Physics & Astronomy, University of
Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, United
States
| | - Rubén Mendoza-Cruz
- Department
of Physics & Astronomy, University of
Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, United
States
- Institute
of Physics, Universidad Nacional Autónoma
de Mexico, A. P. 20-364
Distrito Federal C.P. 01000 Mexico City, Mexico
| | - Lourdes Bazán-Díaz
- Department
of Physics & Astronomy, University of
Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, United
States
- Institute
of Physics, Universidad Nacional Autónoma
de Mexico, A. P. 20-364
Distrito Federal C.P. 01000 Mexico City, Mexico
| | - J. Jesús Velázquez-Salazar
- Department
of Physics & Astronomy, University of
Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, United
States
| | - Rafael Mendoza-Perez
- Department
of Physics & Astronomy, University of
Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, United
States
| | - José Antonio Robledo-Torres
- Advanced Materials
Department, IPICYT, A.C., Camino Presa San José 2055, Lomas 4a Secc. 78216 San Luis Potosi, Mexico
| | - José-Luis Rodriguez-Lopez
- Advanced Materials
Department, IPICYT, A.C., Camino Presa San José 2055, Lomas 4a Secc. 78216 San Luis Potosi, Mexico
| | | | - Robert L. Whetten
- Department
of Physics & Astronomy, University of
Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, United
States
| | - Miguel José-Yacamán
- Department
of Physics & Astronomy, University of
Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, United
States
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40
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Li M, Zhu TS. Modeling the melting temperature of nanoscaled bimetallic alloys. Phys Chem Chem Phys 2016; 18:16958-63. [PMID: 27292044 DOI: 10.1039/c6cp01742h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
T
m(x,D,d) of Pd0.5Pt0.5 nanocrystals versus D with different dimensions.
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Affiliation(s)
- Ming Li
- School of Physics and Electric Information
- Huaibei Normal University
- Huaibei
- China
- Collaborative Innovation Center of Advanced Functional Materials
| | - Tian-Shu Zhu
- School of Physics and Electric Information
- Huaibei Normal University
- Huaibei
- China
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41
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John J, Thomas L, Kurian A, George SD. Enhanced heat diffusion in nanofluid via DNA mediated aggregation. RSC Adv 2016. [DOI: 10.1039/c6ra07855a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Thermal diffusivity increases with different shapes, concentration of gold nanoparticles and also with the addition of ssDNA while the addition of dsDNA found to be ineffective in causing any kind of change in the thermal diffusivity.
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Affiliation(s)
- Jisha John
- Photonics Lab
- Department of Physics
- Catholicate College
- Pathanamthitta
- India-689645
| | - Lincy Thomas
- Photonics Lab
- Department of Physics
- Catholicate College
- Pathanamthitta
- India-689645
| | - Achamma Kurian
- Photonics Lab
- Department of Physics
- Catholicate College
- Pathanamthitta
- India-689645
| | - Sajan D. George
- Centre for Applied Nanosciences
- Department of Atomic and Molecular Physics
- Manipal University
- Manipal
- India-576104
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42
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Pavan L, Rossi K, Baletto F. Metallic nanoparticles meet metadynamics. J Chem Phys 2015; 143:184304. [DOI: 10.1063/1.4935272] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Affiliation(s)
- L. Pavan
- Physics Department, King’s College London, London WC2R 2LS, United Kingdom
| | - K. Rossi
- Physics Department, King’s College London, London WC2R 2LS, United Kingdom
| | - F. Baletto
- Physics Department, King’s College London, London WC2R 2LS, United Kingdom
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43
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Jamshidian M, Thamburaja P, Rabczuk T. A continuum state variable theory to model the size-dependent surface energy of nanostructures. Phys Chem Chem Phys 2015; 17:25494-8. [PMID: 26365098 DOI: 10.1039/c5cp04375a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We propose a continuum-based state variable theory to quantify the excess surface free energy density throughout a nanostructure. The size-dependent effect exhibited by nanoplates and spherical nanoparticles i.e. the reduction of surface energy with reducing nanostructure size is well-captured by our continuum state variable theory. Our constitutive theory is also able to predict the reducing energetic difference between the surface and interior (bulk) portions of a nanostructure with decreasing nanostructure size.
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Affiliation(s)
- Mostafa Jamshidian
- Department of Mechanical Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran.
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44
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Loukhovitski BI, Sharipov AS, Starik AM. Physical and Thermodynamic Properties of AlnCm Clusters: Quantum-Chemical Study. J Phys Chem A 2015; 119:1369-80. [DOI: 10.1021/jp5108087] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Boris I. Loukhovitski
- Central Institute of Aviation Motors, Moscow, Russia Scientific Educational
Centre “Physical-Chemical Kinetics and Combustion”, Aviamotornaya 2, Moscow 111116, Russia
| | - Alexander S. Sharipov
- Central Institute of Aviation Motors, Moscow, Russia Scientific Educational
Centre “Physical-Chemical Kinetics and Combustion”, Aviamotornaya 2, Moscow 111116, Russia
| | - Alexander M. Starik
- Central Institute of Aviation Motors, Moscow, Russia Scientific Educational
Centre “Physical-Chemical Kinetics and Combustion”, Aviamotornaya 2, Moscow 111116, Russia
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