ICME 2012 HW1

< ICME 2012 Overview

Author(s): Laalitha Liyanage

License

By using the codes provided here you accept the the Mississippi State University's license agreement. Please read the agreement carefully before usage.

Overview

This homework is about bridging data from electronic length scale to atomistic length scale. Properties of aluminum calculated through first principles calculations (using quantum mechanics) are used to develop an interatomic potential for use in atomistic simulations (using classical mechanics).

Density Functional Theory (DFT) calculations

The input decks for DFT calculations are designed to use the Vienna Ab initio Software Package (VASP). VASP executable, pseudopotential files (POTCAR) are placed in

/home/laalitha/ICME_share 

VASP executable could be run on Mississippi State University's computer clusters RAPTOR and TALON as well as on computational servers JAVELIN and APEX. VASP executable would not execute in any other machine due to the dependencies on dynamically linked libraries. Before using VASP executable it is essential to do

swsetup openmpi-intel-64

For systems with number of atoms > 20 use the clusters (TALON and RAPTOR) for computation, with a maximum number of 48 processors.

Any difficulties using the executable could be reported to Laalitha.[1]

• Energy vs Volume curves for Aluminum
• Calculation of elastic constants
• Surface formation energy calculation for fcc (111), (110) and (100)
• Generalized Stacking Fault energy curve for Al(111)
• Extrinsic and intrinsic generalized stacking fault energies for Al (111)
• Vacancy formation energy calculation for Aluminum
• Interstitial formation energy for Aluminum

Interatomic Potential Generation

This sections include scripts that outlines a systematic methodology to generate an interatomic potential for a single element (specifically fcc metal systems) in the Modified Embedded Atom Method formalism. The methodology is published in Journal of Nuclear Materials

A presentation by Mark Tschopp on the subject are available here

The following links will lead you to the associated Python and MATLAB scripts of the methodology tailored to a fcc system. Before using the MATLAB scripts always do

swsetup matlab

or add it to your ~/.bashrc file.

• Script 1 - Calculation of material properties in fcc
• Script 2 - Potential space evaluation
• Script 3 - Potential space sampling
• Script 4 - Analytical model generation
• Script 5 - Weight determination of target properties
• Script 6 - Evaluation of uncertainties in goal values