scholarly journals Structural properties of Rhn (n=2 ∼ 100) clusters by using Gupta potential with the simulation of quenching method

2013 ◽  
Vol 4 (3) ◽  
pp. 235-244
Author(s):  
H. -M. Duan
Keyword(s):  
Structural Properties ◽  
Quenching Method ◽  
Gupta Potential

STRUCTURAL PROPERTIES OF BIMETALLIC CLUSTERS FROM DENSITY FUNCTIONAL CALCULATIONS

2005 ◽  
Vol 19 (15n17) ◽  
pp. 2339-2344 ◽  
Author(s):  
EVA M. FERNÁNDEZ ◽  
LUIS C. BALBÁS ◽  
LUIS A. PÉREZ ◽  
KARO MICHAELIAN ◽  
IGNACIO L. GARZÓN
Keyword(s):  
Structural Properties ◽  
Density Functional ◽  
Geometry Optimization ◽  
Model Potential ◽  
Bimetallic Clusters ◽  
Many Body ◽  
Generalized Gradient ◽  
The Many ◽  
The One ◽  
Gupta Potential

The structural properties and energy ordering of the lowest lying isomers of bimetallic ( CuAu )n and ( PtPd )n, n=5-22 clusters have been investigated by means of density functional theory (DFT) in the generalized gradient approximation (GGA). The initial cluster geometry optimization is performed by using a genetic algorithm with the many body Gupta potential. This technique provide a distribution of the lowest energy cluster structures, that are further reoptimized using the DFT-GGA methodology. The energy ordering of isomers obtained with the Gupta potential does not agree, in general, with the one obtained using DFT-GGA for the two bimetallic clusters investigated. However, the lowest energy strucutures of the ( CuAu )n nanoalloy show icosahedral patterns in agreement with the results obtained with the model potential. For the ( PtPd )n clusters segregation effects are found, where the Pt atoms are forming the cluster core and the Pd atoms are on the cluster surface, in agreement with previous calculations using the many body Gupta potential.

The Effect of PbO on the Physical and Structural Properties of Borate Glass System

2016 ◽  
Vol 846 ◽  
pp. 177-182 ◽  
Author(s):  
Mardhiah Abdullah ◽  
S.N.E. Shafieza ◽  
Azman Kasim ◽  
Azhan Hashim
Keyword(s):  
Molar Volume ◽  
Structural Properties ◽  
Glass Network ◽  
Oxide Glass ◽  
Sodium Borate ◽  
Ftir Spectral Analysis ◽  
Good Reputation ◽  
Quenching Method ◽  
Xrd Patterns ◽  
Research World

Borate is one of the most popular oxide glass being used in glass research world wide. Due to good reputation, therefore lead sodium borate glasses with compositions (90 - x) B2O3 + 10ZnO + xPbO (where = 15, 20, 25, 30 and 35 mol %) have been prepared by using melt-quenching method. In this work, their physical and structural properties with respect to PbO content has been investigated. The densities of these glass samples were increased from 3946.2 kg/m3 to 5107.2 kg/m3 with an increase in PbO concentration. The molar volume are found to vary from 23.78 × 10-6 m3mol-1 to 24.39 × 10-6 m3mol-1 with respect to PbO content as well. The density and molar volume show inversed result respectively. The FTIR spectral analysis indicates that with the addition of PbO contents in the glass network, structural units of BO3 are transformed in BO4. There are no sharp peaks were observed in XRD patterns of the glass samples which confirmed the amorphous nature of the glass. Meanwhile, the micro hardness of these glass samples were also increased from 189 Pa to 355 Pa with increases on PbO content. The results will be discussed and presented in details.

Hardness and Structure of Er3+:Sm3+ Co-Doped Oxychloride Zinc Tellurite Glass

2017 ◽  
Vol 268 ◽  
pp. 43-47
Author(s):  
S.N. Nazhirah Mazlan ◽  
Ramli Arifin ◽  
Sib Krishna Ghoshal
Keyword(s):  
Structural Properties ◽  
Tellurite Glass ◽  
Glass Composition ◽  
Rare Earth Ions ◽  
Host Matrix ◽  
High Performing ◽  
Co Doping ◽  
Quenching Method ◽  
Ir Bands

Glass samples with composition of (64-x)TeO2 + (x)ZnO + 15 ZnCl2 + 0.5 Sm2O3 + 0.5 Er2O3 (x = 20, 25 and 30 mol%) are prepared by melt quenching method. The season for co-doping with rare earth ions such as samarium (Sm3+) and erbium (Er3+) is to explore the feasibility of their simultaneous exploitation as high performing up-converted lasing materials. The role of varying modifier of ZnO concentration in improving the hardness and structural properties are evaluated. The density is observed to reduce and ionic packing density is augmented with increasing concentration of ZnO. Glass with 25 mol% of ZnO revealed the optimum hardness of 2830 N/mm2. Incorporation of Zn2+ into the tellurite host matrix is found to shift the IR bands position slightly without altering their intensity. Bonding vibrations corresponding to bending of TeO3 unit (784-762 cm-1), stretching of TeO4 units (678-676 cm-1) and Zn-O bonds (462-452 cm-1) are evidenced. Incorporation of ZnO as modifier is established to enhance the hardness and improved the structural properties. The proposed glass composition may be useful for industrial purposes.

Physical and Structural Properties of Neodymium Doped Lithium Boro-Tellurite Glasses

2019 ◽  
Vol 290 ◽  
pp. 53-59
Author(s):  
Yahya Norihan ◽  
Ahmad Ridzwan Bin Ab Rahim ◽  
Mardhiah Abdullah
Keyword(s):  
Structural Properties ◽  
Xrd Analysis ◽  
Ftir Spectra ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Prepared Glass ◽  
Amorphous Nature ◽  
Quenching Method ◽  
Xrd Patterns

Nd3+ doped lithium borotellurite glasses were successfully been prepared by conventional melt-quenching method with the chemical composition (70.0)B2O3-(5.0)TeO2-(25.0-x) Li2CO3-xNd2O3 (where x = 0.0, 0.2, 0.4, 0.6, 0.8 and 2.0 mol%) by varying the Neodymium content. The physical properties such as density, molar volume and oxygen packing density were measured. The structural properties have been studied through X-ray diffraction (XRD) analysis and Fourier Transform Infrared (FTIR) spectroscopy. The XRD pattern has been used to confirm the amorphous nature of the glass samples. There are no sharp peaks were observed in XRD patterns of the glass samples which confirmed the amorphous nature of the glass. FTIR spectra were used to analyse the functional groups present in the glass samples. The FTIR spectra reveal the presence of B-O-B, B-O, BO3, BO4,Te-O and characteristic of the hydrogen bond in the prepared glass samples.

The Structural Properties of Trivalent Rare Earth Ions (Er3+) Doped Borotellurite Glass

2014 ◽  
Vol 69 (2) ◽  
Author(s):  
E. S. Nurbaisyatul ◽  
K. Azman ◽  
H. Azhan ◽  
W. A. W. Razali ◽  
A. Noranizah
Keyword(s):  
Molar Volume ◽  
Structural Properties ◽  
Rare Earth Ions ◽  
Physical Parameters ◽  
Absorption Bands ◽  
Bending Vibrations ◽  
Laser Applications ◽  
Stretching Vibration ◽  
Trivalent Rare Earth ◽  
Quenching Method

Six samples of borotellurite glasses with system (80-x)TeO2- 10B2O3 - 10PbO - xEr2O3 (x=0.0, 0.5, 1.0, 1.5, 2.0, 2.5 mol%) have been prepared by using the conventional melt-quenching method. Some basic physical parameters such as density and molar volume were measured. The result reveals that the density and molar volume increases with the increases of mol% of Er2O3. The amorphous nature of the glass has been characterized using X-ray Diffraction (XRD) and all glasses are found to be amorphous in nature. The structure was analysed by FTIR spectroscopy. The FTIR spectra were recorded at room temperature in the frequency range from 650 to 4000  cm-1 using Attenuated Total Reflectance (ATR) method. From the IR results, the absorption bands were found to be in the range 667-669 cm-1, 710-712 cm-1, 880-887 cm-1, 981-997 cm-1 and 1190-1204 cm-1 which correspond to the stretching and bending vibrations mode. The absorption peaks around 1386-1388 cm-1 and 3741-3748 cm-1 which ascribed to the hydroxyl-metal bond and hydroxyl-hydrogen bond stretching vibration also have been observed. The FTIR results demonstrate that the existing of erbium in the composition leads to good structural properties thus creating potential for this glass in laser applications.

Newborn's Preference for Faces

1996 ◽  
Vol 1 (3) ◽  
pp. 200-205 ◽  
Author(s):  
Carlo Umiltà ◽  
Francesca Simion ◽  
Eloisa Valenza
Keyword(s):  
Visual System ◽  
Structural Properties ◽  
Sensory Properties ◽  
Human Face ◽  
System Experiment ◽  
Face Experiment

Four experiments were aimed at elucidating some aspects of the preference for facelike patterns in newborns. Experiment 1 showed a preference for a stimulus whose components were located in the correct arrangement for a human face. Experiment 2 showed a preference for stimuli that had optimal sensory properties for the newborn visual system. Experiment 3 showed that babies directed their attention to a facelike pattern even when it was presented simultaneously with a non-facelike stimulus with optimal sensory properties. Experiment 4 showed the preference for facelike patterns in the temporal hemifield but not in the nasal hemifield. It was concluded that newborns' preference for facelike patterns reflects the activity of a subcortical system which is sensitive to the structural properties of the stimulus.

Investigation of the structural properties of crystallized Fe-(Cu)-Sm-B ribbons

1998 ◽  
Vol 08 (PR2) ◽  
pp. Pr2-47-Pr2-50
Author(s):  
O. Crisan ◽  
J. M. Le Breton ◽  
F. Machizaud ◽  
A. Jianu ◽  
J. Teillet ◽  
...  
Keyword(s):  
Structural Properties
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