Photonic crystals in biology

Poster Session, Tuesday, June 15
Theme A1 - B702
Physical Properties of Cu-nanoparticles: A Molecular Dynamics Study
H.Y 1 *, H.H.Kart 1 ,andT.Ç 2
1
2
Department of Chemical Engineering, Texas A&M University, Texas, TX 77843-3122, USA
Abstract- The physical properties of Cu nanoparticles diameters ranging from 1 nanometers to 10 nanometers are studied using Molecular
Dynamics (MD) simulations. The interactions between atoms are represented by Quantum Sutton-Chen (Q-SC) many-body interaction
potential suitable for transition metals. This method is suitable for modeling large systems for a very long time scales. Molecular dynamics
simulations of the Cu-nanoparticles are performed at temperatures ranging from 100 K to well beyond melting temperature for the
nanoparticles using the MPiSiM code to study their behavior at low temperatures as well in the molten state. Simulation results such as
kinetic energy, potential energy, heat capacity and latent heat of the fusion are compared with the available experimental bulk results.
Nanoparticles with diameter of 1 nanometer (nm) to 10
nm exhibit physical, chemical and electronic properties
different from those of bulk atoms and single molecules
due to the large fraction of surface atoms. The physical
properties of nanoparticles are expected to change
gardually from molecular to bulk crystaline as the number
of atoms increases. Studies of physical properties of
nanoparticles in this range by experiments presents
difficulties. It is well known that the melting temperature
decreases with the number of atoms in the nanoparticles
[1-3]. Metal nanoparticles (Cu) are important for various
applications [4,5]; eg. they are used as interconnects for
computers and as antibacterials. They may also have
potential applications in the future applications in thermal
management systems, gas separations, in microelectronics.
Hence, it is important to understand the physical properties
of copper nanoparticles.
It is also shown that the order of values of heat capacity
and latent heat of fusion are compatible with the bulk ones
of theoretical and experimental data for the copper.
* Corresponding author: hyildirim053@pau.edu.tr
[1] H. Gleiter, Prog. Mater. Sci. 33, 223 (1989).
[2] M. Yaedon, J. C. Yang, R. S. Averback, J. W. Bullard and J.
M. Gibson, NanoStruct. Mat. 10, 731 (1998).
[3] Y. Qi, T. Cagin, W. L. Johnson, W. A. Goddard III, J. Chem.
Phys. 115, 385 (2001).
[4]http://www.azom.com/details.aspArticleID=1066.
[5] A. M. Mazzone, Phil. Mag. B 80, 95 (2000)
[6
(2009).
[7] H. H. Kart, M. Tomak and T. Cagin, Modeling Simul. Mater.
Sci. Eng. 13, 1 (2005).
[8] T. Cagin, Y. Qi, H. Li, Y. Kimura, H. Ikeda, W. L. Johnson,
and W. A. Goddard III, MRS Symp. Ser. 554, 43 (1999).
Figure 1. The variation of total energy as a function of diameter
for Cu nanoparticles.
In this work, we apply molecular dynamics (MD)
methods using the quantum Sutton-Chen (Q-SC) [6-8]
many body force field to simulate the nanoparticles with
the diameter size from 1 nm to 10 nm to investigate the the
thermodynamical properties of the Cu nanoclusters at low
and high temperatures. In summary, we have shown that
MD approach is a reliable method to study the physical
properties of the nanoparticles. Melting temperatures of
the copper nanoparticles decrease as the size of the
nanoparticle decreases as seen in Fig. 1. The bond leght of
the atoms is increased as a function of temperature as
shown in Fig. 2.
100 K 300 K 700 K 1500 K
Figure 2. Typical snapshops of 2-nanometer size Cu
nanoparticles at various temperatures.
6th Nanoscience and Nanotechnology Conference, zmir, 2010 255