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exercises:2017_ethz_mmm:bands_2 [2017/05/17 11:15] – dpasseroneexercises:2017_ethz_mmm:bands_2 [2020/08/21 10:15] (current) – external edit 127.0.0.1
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 </code> </code>
  
-go in the directory where you want to put the exercise and do:+ 
 +**go to your scratch directory:** 
 +<code> 
 +cd /mnt/scratch/your_username 
 +</code> 
 +and copy there the tar file of the exercise:
 <code> <code>
 cp /home/cpi/exercise_11.tar ./ cp /home/cpi/exercise_11.tar ./
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 ===TASK_0==== ===TASK_0====
  
-The batch script // **run**// contain the instruction to run a quantum-espresso DFT calculaiton+The batch script // **run**// contains the instruction to run a quantum-espresso DFT calculation
 for a conventional cell of Si (ibrav=1 for simple cubic cell). for a conventional cell of Si (ibrav=1 for simple cubic cell).
 As you can see in the file, 8 atoms are included in the cell of parameter a=5.43A. As you can see in the file, 8 atoms are included in the cell of parameter a=5.43A.
 The primitive cell (ibrav=2 for fcc) would contain only 2 atoms and would not be cubic. The primitive cell (ibrav=2 for fcc) would contain only 2 atoms and would not be cubic.
-The scirpt is ment to run a calculation to optimize the wavefuntion of the system and to compute the total energy. +The script is meant to run a calculation to optimize the wavefunction of the system and to compute the total energy. 
-A sinlge k point, Gamma, is used for the summation over the Brillouin Zone.+A single k point, Gamma, is used for the summation over the Brillouin Zone.
  
 <note important> <note important>
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   * the type of lattice (ibrav) is specified   * the type of lattice (ibrav) is specified
   * the coordinates of the atoms are provided in crystal coordinates   * the coordinates of the atoms are provided in crystal coordinates
-  * the Monkhorst-Pack grid (in this case only Gamma point) is specifyed for the BZ sums+  * the Monkhorst-Pack grid (in this case only Gamma point) is specified for the BZ sums
   * how many electrons do we have in the system?   * how many electrons do we have in the system?
-  * how many occupied egigenvector do we have for each k-point (the occupation is printed in the output for each k-point after the energies of the eigenvalues belonging to the k-point+  * how many occupied eigenvector do we have for each k-point (the occupation is printed in the output for each k-point after the energies of the eigenvalues belonging to the k-point
  
 Submit the calculation to the queue Submit the calculation to the queue
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 </code> </code>
  
-Have a look to th eoutput generated: si.out+ 
 +**PLEASE NOTE:** 
 + 
 +<code> 
 +qstat | grep your_username 
 +</code> 
 +if in the 5th column you see    
 +  * "Q" it means that your job is still waiting in the queue 
 +  * "R" your job is running 
 +  * "C" your job is completed 
 +If you do not get anything your job was completed as well 
 + 
 + 
 + 
 +Have a look to the output generated: si.out
   * identify where the symmetry operations used by the code are listed   * identify where the symmetry operations used by the code are listed
   * identify the k-points used during the calculations    * identify the k-points used during the calculations 
   * find where the eigenvalues (provided in eV) for each k-point are printed   * find where the eigenvalues (provided in eV) for each k-point are printed
-  * find the total energy of teh system+  * find the total energy of the system
  
 to find  the total energy of the system you can also type: to find  the total energy of the system you can also type:
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 ===TASK_2=== ===TASK_2===
-Here the //**run**// script contains teh data to run a calculation for a large Si cell +Here the //**run**// script contains the data to run a calculation for a large Si cell 
-There are 216 atoms corresponding to 3x3x3 of the conventional cell used in the previuos calculations+There are 216 atoms corresponding to 3x3x3 of the conventional cell (8 atoms per cell in the conventional cell thus 3*3*3*8 atoms in total) used in the previous calculations
 <note important> <note important>
 submit the calculation (it will take ~10 minutes to be completed) submit the calculation (it will take ~10 minutes to be completed)
 compare the total energy (**THAT WE CALL E27**)obtained in this calculation with the ones obtained in task_0,0b,0c,1   compare the total energy (**THAT WE CALL E27**)obtained in this calculation with the ones obtained in task_0,0b,0c,1  
-  *  why the total energy obtained in TASK_1 is closer to E27/27 compared to the energies obtained in TASKS 0,0b,0c?  +  *  why the total energy obtained in TASK_1 is closer to **E27**/27 compared to the energies obtained in TASKS 0,0b,0c?  
   *  Compare the eigenvalues that you have now at the Gamma k-point with the eigenvalues you had on the different k-points for the calculation of TASK_1. All the eigenvalues obtained in TASK_1, that are subdivided in different k-points are now grouped in a single k-point.   *  Compare the eigenvalues that you have now at the Gamma k-point with the eigenvalues you had on the different k-points for the calculation of TASK_1. All the eigenvalues obtained in TASK_1, that are subdivided in different k-points are now grouped in a single k-point.
   * How many k-points are used in the calculation of TASK_1 as listed in si.out? why not 27?   * How many k-points are used in the calculation of TASK_1 as listed in si.out? why not 27?
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 In the input I specified in "crystal coordinates" (but units of the reciprocal lattice vectors not units of the unit cell vectors) In the input I specified in "crystal coordinates" (but units of the reciprocal lattice vectors not units of the unit cell vectors)
 the 100 k-points used to sample the L-G and G-X symmetry lines. the 100 k-points used to sample the L-G and G-X symmetry lines.
-The k-points in sibands.out are given in cartesian cooridnates in units of 2pi/a.(as will be used in TASK_5)+The k-points in sibands.out are given in cartesian coordinates in units of 2pi/a.(as will be used in TASK_5)
 <note important> <note important>
 submit the calculation submit the calculation
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 The aim of tasks 4 and 5 is to get familiar with what happens to the representation of bandsturctures The aim of tasks 4 and 5 is to get familiar with what happens to the representation of bandsturctures
 if we change the simulation cell. if we change the simulation cell.
-In task 4 I assing to the conventional cell of Si a large lattice parameter,+In task 4 I assign to the conventional cell of Si a large lattice parameter,
 the 8 Si atoms of the cell will then be quite far one each other and will almost not interact the 8 Si atoms of the cell will then be quite far one each other and will almost not interact
 This is of course not a correct representation of Bulk Si, it is instructive to see This is of course not a correct representation of Bulk Si, it is instructive to see
-that the bands will reduce to flat lines corresponding to the s and p orbitals o fthe isolated Si atoms+that the bands will reduce to flat lines corresponding to the s and p orbitals of the isolated Si atoms
 <note important> <note important>
 following the procedure of TASK_3 submit the calculation and plot the bandstructure following the procedure of TASK_3 submit the calculation and plot the bandstructure
exercises/2017_ethz_mmm/bands_2.1495019745.txt.gz · Last modified: 2020/08/21 10:15 (external edit)