Computational Study of Ag doped Au Nanoalloy Clusters Prabhat Ranjan1, Tanmoy Chakraborty*2, Ajay Kumar3 1,3 - Dept. of Mechatronics, 2*-Dept. of Chemistry Manipal University Jaipur
Introduction
Result
Bi-metallic Nanoalloy clusters are getting extensively popular due to its many fold applications in the field of science and engineering. The compound formed between AgAu has gained considerable interest because they possess unique optical, electronic and magnetic properties, which have extensive application in the field of medicine, biophysics and nanoscience. In this venture, we have analyzed the experimental properties of AgAun (n=1-7) nanoalloy clusters invoking DFT methodology. A nice correlation has been made between experimental property and our computed descriptors.
Species
HOMO-LUMO gap (eV)
Electronegativity (eV)
Hardness (eV)
Softness (eV)
Electrophilicity Index (eV)
AgAu
2.017
4.318
1.009
0.495
2.159
AgAu2
0.394
4.654
0.197
2.534
2.327
AgAu3
1.395
5.289
0.696
0.717
2.645
AgAu4
0.255
5.423
0.127
3.909
2.712
AgAu5
1.432
4.272
0.716
0.698
2.136
AgAu6
0.134
5.269
0.067
7.501
2.635
AgAu7
0.686
4.307
0.342
1.458
2.153
Table 1: A Collection of computed DFT based Descriptors of Ag-Au Nano clusters 2.5 2 1.5
HOMO - LUMO Gap
y = 1.9996x + 0.0009 R² = 1
1 0.5 0 0
0.2
0.4
0.6
0.8
1
1.2
Global Hardness
Figure 3: A nice correlation between Global Hardness Vs HOMO-LUMO Gap Figure 1. Nanoalloy clusters of Ag-Au.
Methodology Optimization of the structures of instant Nanomaterials have been performed using DFT methodology in terms of Local Density Approximation (LDA),with restricted spin using double zeta basis set (DZ). From the optimized geometries some important conceptual DFT based descriptors viz. Global Hardness (η), Global Softness (S), Global Electrophilicity Index (ω) and Global Electronegativity (χ) have been calculated.
Discussion
A nice correlation is established between experimental band-gap with our computed descriptors. Our evaluated hardness runs hand in hand with experimental band gap of Ag-Au Nano clusters.
From the table 1, it is clear that AgAu is least reactive species whereas AgAu6 will exhibit maximum response.
References: [1] A. Zabet-Khosousi, A.-A. Dhirani, Charge transport in nanoparticle assemblies, Chem. Rev.108 (2008) 40724124. [2] M.C. Daniel, D. Astruc, Gold nanoparticles: assembly, supramolecular chemistry, quantum-size-related properties, and applications toward biology, catalysis, and nanotechnology, Chem. Rev. 104 (2004) 293-346. [3] S. K. Ghosh, T. Pal, Interparticle coupling effect on the surface plasmon resonance of gold nanoparticles: from theory to applications, Chem. Rev. 107 (2007) 4797-4862.
Acknowledgement All of the authors are thankful to the management of Manipal University Jaipur for providing the research facility. Figure 2. Electron density distribution at HOMO and LUMO of AgAu7 molecule