Molecular Dynamics simulations Surface interaction energy

In summary, the gold cluster has cubic shape at the initial state and surface energies can be obtained using a slab model in which you orient the surface of interest to be normal to z-axis (for example). The energy in z-direction can be determined using a vacuum gap above the surface of a thickness > 1nm or by using classical potentials.
  • #1
dikmikkel
168
0
Hey,
I've simulated a solid metal cluster of gold fcc100
And a surface Platinum in fcc111 using a classical mechanical approach.
Do you think i could get the surface free energies(the ones to use in determining the Wulff shape) from periodic boundary conditions and if so how? I am really confused, i need to make an approximation of the height and width of the melted particle so i would like the energy in the UP/z direction.

The gold cluster is cubic at the initial state btw.
 
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  • #2
Surface energies can be obtained using a slab model in which you orient the surface of interest to be normal to z-axis (for example). You apply periodic boundary conditions in x and y but in z-direction you have two options. Either still using periodic boundary conditions but leave a vacuum gap above the surface of a thickness > 1nm (a convergence test is needed here) or if you are using classical potentials you can actually remove the periodicity in z and use a vacuum boundary condition in this direction. IN that case
Esurf=(Eslab-Ebulk)/2 , The factor of two because you have two exposed surfaces.

The nanoparticle/ cluster approach you described above is not common and indeed may not always be useful to calculate the surface energy beacause:
1- All the faces of the cluster should represent the same surface. This is very hard to achieve unless the material has a crystal structure of high symmetry.
2- One may need a very large cluster to guarantee convergence.
 
  • #3
Hi again,
Thank you for the clear answer.
I just want to estimate the energies for determining how high and wide the cluster will be at some state.
I simulate an actual surface with an on it resting cluster, and not a potential difference, so it is a bit more coumbersome i think.

But how will i determine the wulff shape from the initial state, i have only 6 faces and to me it looks like it will be a triangle(3d). Do you have any litterature to recommend, this stuff is mabye not so much at my level(undergraduate).

Thanks again
Edit:
Btw. it is the contanct energy between cluster and surface which is interesting
 
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Related to Molecular Dynamics simulations Surface interaction energy

1. What is the purpose of Molecular Dynamics simulations for surface interaction energy?

Molecular Dynamics simulations are used to study the behavior of molecules at the atomic level. In the context of surface interaction energy, these simulations allow scientists to observe and analyze how molecules interact with each other at the surface of a material, providing valuable insights into surface properties and potential applications.

2. How are Molecular Dynamics simulations used to calculate surface interaction energy?

Molecular Dynamics simulations use mathematical algorithms to model the movement and interactions of individual atoms and molecules. By tracking the positions and energies of these particles, the simulations can calculate the total energy of the system, including the surface interaction energy between molecules. This information can then be used to analyze and predict surface properties and behavior.

3. What factors affect surface interaction energy in Molecular Dynamics simulations?

There are several factors that can influence surface interaction energy in Molecular Dynamics simulations. These include the types of molecules involved, their distance and orientation from each other, and the presence of any external forces or constraints. Additionally, the temperature and pressure of the simulation environment can also impact surface interaction energy.

4. How accurate are Molecular Dynamics simulations for predicting surface interaction energy?

Molecular Dynamics simulations are considered to be a highly accurate method for predicting surface interaction energy, as they take into account the movements and interactions of individual atoms and molecules. However, the accuracy of the results depends on the quality of the simulation parameters and the potential limitations of the model used.

5. What are some real-world applications of Molecular Dynamics simulations for surface interaction energy?

Molecular Dynamics simulations have a wide range of applications in fields such as material science, nanotechnology, and biophysics. They can be used to study the behavior of materials at the atomic level, understand surface properties, and design new materials with specific surface interactions for various applications, such as drug delivery, catalysis, and electronic devices.

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