INSTRUCTIONS FOR DAY 1, EXERCISE 3


Note that the following color code has been used in this instruction sheet:

Broad headings are in red.

File names are in magenta.

Phrases to be typed into the command line are in blue.

Input parameters are in dark green.


A very brief reminder of useful linux commands:


In this exercise, you will perform simple scf (self-consistent field) calculations on alumin(i)um.


There are 2 main ways in which Al differs from Si:

  1. It has the FCC crystal structure, instead of the diamond structure.

  2. It is a metal, and therefore has to be treated differently.


You will see the following files:

day1_exercise3_instructions.html this file!

Al.sample.in this is a sample input file.

Al.sample.sh this is a sample shell script that you can use (optionally) .


For each calculation that you will run, you can use Al.sample.in as a template that you can copy to another file and then edit. Alternatively, you can use shell scripts to automate this process.















Make input files of the form al_degauss_nk_scf.in (inserting the appropriate values of degauss and nk).

In order to do this, you can either edit your input files manually, or use the shell script Al.sample.sh

(If doing the latter, read the shell script carefully and see whether you need to insert additional values or lines).




(of course, you should substitute the appropriate values).



xmgrace al.m-v* &


The 'true' converged result is obtained in the limit of zero smearing and an infinite number of k-points.

Based upon this, decide what values of nk1=nk2=nk3 and degauss you consider satisfactory.

(Note: you will have to achieve some sort of compromise between accuracy and computational time!)


(Optional extra assignment: repeat this whole section using Gaussian smearing instead of Marzari-Vanderbilt smearing. Which smearing works better?)


When you run this, you will be prompted to supply:


Optional extra assignments: