Computational Lab 2

Local Optimization of Nanoparticles with Density Functional Theory: Calculating Binding and Cohesive Energies

In this lab, you will learn how to do local optimization of nanoparticles where the potential energy surface is found using an electronic structure method called density functional theory (DFT). When doing local optimization with DFT, two optimizations take place: First the ideal location of all electrons in the chemical system is found for fixed nuclei, then this information is used to move the nuclei towards the local minimum. The energies of the local minimum of various species will be used to calculate binding and cohesive energies which are defined throughout the lab.

This lab contains the following simulations. Tutorial for running VASP can be found in the first one.

1. VASP tutorial through calculating the energy of Pt32
2. Calculations of Pt38
3. Calculations of reference atoms and molecules
4. Calculations of Pd@Pt core-shell particle.
5. Calculations of Pt@Pd core-shell particle.
6. Calculation of Pd@Pt O and Pt38 O .
7. Calculations of O bonded on your own core-shell nano particle.
8. Calculations of simple chemical reactions.

Suggestion: Keep your data for binding and cohesive energies in an excel spreadsheet to stay organized! To find the cohesive energy take the energy that you calculated for the Pt32 particle and subtract off 32 times the energy of a single atom:

E_cohesive_Pt32 = E_Pt32 - 32*E_Pt1

• When you are finished examining the results of the run, you can wrap up and save the old run neatly by typing vfin.pl run#

• With the above simulations finished, use the results to answer questions here.