Integration of acetylenic carbon clusters and silver clusters: template synthesis and stability enhancement

AbstractSingle crystals of sapphire were implanted at room temperature with 300 keV-Ag+. The metal precipitate was characterized by a multitechnique approach including RBS, optical absorption and Raman spectroscopy. RBS measurements were used to determine the depth-profiles of the implanted ions. Ag depth profiles, derived from RBS are in good agreement with the results predicted by Monte Carlo simulations. Linear absorption spectroscopy has been used to characterize the effects of the ion fluence on the optical properties of the metal colloids in the UV-Vis region. The broad absorption band due to the surface plasmon resonance shows an appreciable red-shift when the fluence of bombarding ions increases. Raman scattering from acoustic vibrations of the silver clusters progressively shifts toward the laser frequency with increasing implantation dose. From low-frequency Raman spectra an evaluation of the average size of metal aggregates was derived.

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Interaction of Nitric Oxide and Nitric Oxide Dimer with Silver Clusters

Computing Letters ◽

10.1163/157404005776611268 ◽

2005 ◽

Vol 1 (4) ◽

pp. 253-258 ◽

Cited By ~ 1

Author(s):

V.E. Matulis ◽

O.A. Ivashkevich ◽

V.S. Gurin

Keyword(s):

Nitric Oxide ◽

Density Functional Theory ◽

Cluster Model ◽

Density Functional ◽

Bond Formation ◽

Silver Cluster ◽

Silver Clusters ◽

Functional Theory ◽

Nitric Oxide Dimer

Study of interaction of NO and (NO)2 molecules with silver clusters has been carried out using the hybrid method S2LYP based on density functional theory (DFT). The role of cluster charge and site of adsorption on N–O stretch frequency, adsorption energy and geometry has been investigated. Four cluster models of different size have been used for simulation of (NO)2 adsorption on Ag{111} surface. The pronounced effect of N–N bond shortening in comparison with gaseous (NO)2 has been found due to adsorption of (NO)2 on silver cluster. This phenomenon is important as possible pathway of N–N bond formation in catalytic fragmentation of NO molecule. The calculations showed that the silver octamer is the best candidate for simulation of formation and fragmentation of (NO)2 on Ag{111} surface within the cluster model.

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ABSORPTION OF SOME SMALL SILVER CLUSTERS: DFT AND CASPT2 CALCULATIONS

Vietnam Journal of Science and Technology ◽

10.15625/2525-2518/55/6a/12367 ◽

2018 ◽

Vol 55 (6A) ◽

pp. 72

Author(s):

Ngo Tuan Cuong

Keyword(s):

Absorption Spectra ◽

Density Functional ◽

Noble Gas ◽

Silver Cluster ◽

Dft Method ◽

Basis Sets ◽

Silver Clusters ◽

Excitation Energies ◽

Complete Active Space ◽

Td Dft

Two quantum chemical methods which are the time-dependent density functional theory (TD-DFT) and the complete active space CASPT2/CASSCF have been used in modeling absorption spectra of silver clusters Agn (n = 2, 3, 4, 6, 8). There is an overall good agreement between TD-DFT and CASPT2 results for transition energies. The absorption spectra of the Agn clusters examined can reasonably be simulated using the excitation energies obtained by either TD-DFT or CASPT2 method. The main result emerged from this calculation is that the TD-DFT method is suitable for treatment of excited states of Ag clusters. The choice of specific functionals and basis sets to be used in some cases induces important effects on the calculated spectra. It is also noteworthy to mention that for some clusters, the neutral Ag6 for instance, the effect of noble gas environment is significant, while for some others such as the neutral Ag8, it is not. Therefore, carrying out TD-DFT calculations to reproduce and to assign a given structure to an experimental absorption spectrum of a silver cluster, it is not only to select suitable functionals but also to take enough effects of environments into account.

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Theoretical Study of Stability, Structure, and Optical Spectra of Ultra-Small Silver Clusters Using Density Functional Theory

10.26434/chemrxiv.13272443 ◽

2020 ◽

Author(s):

mohsen farshad ◽

Duwage Perera ◽

jayendran Rasaiah

Keyword(s):

Density Functional Theory ◽

Formation Mechanism ◽

Density Functional ◽

Cluster Formation ◽

Experimental System ◽

Silver Cluster ◽

Optical Spectra ◽

Structure Stability ◽

Silver Clusters ◽

Functional Theory

Our article is a systematic study toward understanding the mechanism of silver cluster formation. We calculated optical spectra of ultra-small silver clusters using time-dependent density functional theory (TDDFT) and compared our results with time-resolved UV-Vis spectra obtained from pulse radiolysis experiments during early stages of cluster formation. This comparative study indicates that the formation mechanism of silver clusters occurs through both monomer and ion addition growth pathways. Also, we calculated free energy of formation of small cationic and neutral clusters using density functional theory (DFT) which shows the thermodynamic stability of cationic clusters. In a conventional experimental system with the common reducing agents, the formation of cationic clusters is kinetically favored owing to the dominance of charged ions relative to neutral atoms in the system. While we show the stability of small cationic clusters relative to neutral clusters, collectively, we deduce that the monomer addition along with ion addition growth pathway is involved in silver cluster formation mechanism. We further show the effect of solvent and water ligands on structure, stability, and optical properties of small clusters.

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Preparation of gas phase naked silver cluster cations outside a mass spectrometer from ligand protected clusters in solution

Nanoscale ◽

10.1039/c8nr04146f ◽

2018 ◽

Vol 10 (33) ◽

pp. 15714-15722 ◽

Cited By ~ 9

Author(s):

Madhuri Jash ◽

Arthur C. Reber ◽

Atanu Ghosh ◽

Depanjan Sarkar ◽

Mohammad Bodiuzzaman ◽

...

Keyword(s):

Gas Phase ◽

Mass Spectrometer ◽

Thermal Desorption ◽

Silver Cluster ◽

Silver Clusters

Gas phase naked silver clusters were prepared outside the mass spectrometer by thermal desorption of ligands starting from ligand protected clusters.

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STABILITIES AND FRAGMENTATION BEHAVIORS OF Agn CLUSTERS (n = 2–34)

Journal of Theoretical and Computational Chemistry ◽

10.1142/s0219633612500642 ◽

2012 ◽

Vol 11 (05) ◽

pp. 953-964 ◽

Cited By ~ 6

Author(s):

WEI ZHANG ◽

SHU-YAO YAN ◽

ZENG-XIA ZHAO ◽

HONG-XING ZHANG

Keyword(s):

Molecular Orbital ◽

Tight Binding ◽

Silver Cluster ◽

Dft Method ◽

Binding Energies ◽

Silver Clusters ◽

Fragmentation Channel ◽

Highest Occupied Molecular Orbital ◽

Lowest Unoccupied Molecular Orbital ◽

Homo Lumo

A global search on the lowest-energy structures of the medium-sized silver clusters Ag n(n = 21–34) was performed by using a genetic algorithm (GA) coupled with a tight-binding (TB) method. Structures, binding energies per atom, second differences in energies, the energy gaps between the highest occupied molecular orbital and the lowest unoccupied molecular orbital (HOMO–LUMO), and fragmentation behaviors of Ag n(n = 21–34) are investigated by using DFT method. The calculated results show that the neutral silver clusters prefer to decay by evaporation of a monomer except a small sized silver cluster ( Ag 4), which favors a dimmer evaporation. For the collision induced dissociation of cationic silver clusters, decaying a silver atom is found to be the dominant fragmentation channel. But for some small sized cationic silver clusters, a neutral dimmer evaporation is found to be energetically favorable. Our calculated results are consistent with previous studies.

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IR STUDIES OF CHEMISORPTION ON MOLECULAR SURFACES: AMMONIA ON SILVER CLUSTERS

Surface Review and Letters ◽

10.1142/s0218625x96001169 ◽

1996 ◽

Vol 03 (01) ◽

pp. 649-654 ◽

Cited By ~ 10

Author(s):

D.M. RAYNER ◽

L. LIAN ◽

K. ATHANASSENAS ◽

B.A. COLLINGS ◽

R. FOURNIER ◽

...

Keyword(s):

Density Functional ◽

Flow Reactor ◽

Metal Cluster ◽

Action Spectrum ◽

Silver Cluster ◽

Silver Clusters ◽

Flight Mass Spectrometry ◽

Ir Studies ◽

Ag Clusters ◽

Fast Flow

Metal clusters are proposed as models to develop a molecular perspective on surface processes and to increase our understanding in important areas such as heterogeneous catalysis. This goal requires the characterization of small metal-cluster-ligand complexes in as great detail as possible. One avenue is to apply IR spectroscopy to cluster-ligand complexes. Problems of number density and mass selectivity prohibit the use of direct optical absorption methods. We report on progress towards applying infrared multiphoton dissociation, IRMPD, to obtain spectra by direct photodepletion. In this regard the silver-cluster-ammonia system is promising. The action spectrum for IRMPD of Ag 2 NH 3, monitored via the Ag 2 product in a fast-flow reactor, reveals an absorption peak at 1065 cm −1 which is assigned to the −NH3 umbrella mode of the complex. Molecular structure calculations using density-functional theory predict an end-on geometry and are in good agreement with this value. Preliminary results on complexes of larger Ag clusters studied by monitoring the IRMPD depletion of a Ag n NH 3 molecular beam by time-of-flight mass spectrometry are presented. The promise of these systems as models for NH 3 bound to Ag surfaces is discussed.

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Self-Assembly of Silver Clusters into One- and Two-Dimensional Structures as Artificial Intelligent Sensors of Alcohol

10.21203/rs.3.rs-964647/v1 ◽

2021 ◽

Author(s):

Gao Li ◽

Zhaoxian Qin ◽

Sachil Sharma ◽

Yongwu Peng

Keyword(s):

Organic Solvents ◽

Self Assembly ◽

Silver Cluster ◽

Silver Clusters ◽

Two Dimensional ◽

Artificial Intelligent ◽

Atomic Structures ◽

Intelligent Sensors ◽

Crucial Component ◽

Solvent Molecules

Abstract Reggeization and response to external stimulus is an important part of artificial intelligence, which would significantly improve the quality of life in the future. The development of new materials for the design of sensitive and responsive sensors has become a crucial component. Here, two silver cluster-based polymers (Ag-CBPs), including one-dimensional (1D) {Ag22(L1)8(CF3CO2)14(CH3OH)2}n chain and two-dimensional (2D) {[Ag12(L2)2(CO2CF3)14(H2O)4(AgCO2CF3)4](HNEt3)2}n film, are designed and used to simulate the human nose - an elegant sensor to smells, to distinguish organic solvents. We study the relationship between the atomic structures of Ag-CBPs determined by X-ray diffraction and electrical properties in the presence of organic solvents (e.g. methanol, ethanol). The ligands, cations and the ligated solvent molecules not only play an important role in the self-assembly process of Ag-CBP materials, but also determine their physiochemical properties. An application of cluster-based polymers is demonstrated in the artificial intelligent sensors.

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