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exercises:2018_ethz_mmm:mc2018

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exercises:2018_ethz_mmm:mc2018 [2018/03/06 14:22] – dpasseroneexercises:2018_ethz_mmm:mc2018 [2020/08/21 10:15] (current) – external edit 127.0.0.1
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-====== Monte Carlo simulations for the estimation of molecule pair interaction ====== +====== Monte Carlo simulations for the estimation of  pair interactions ====== 
 =====  ===== 
 In this exercise you will perform a MC simulation for different coverages of "sumanene" mlecules In this exercise you will perform a MC simulation for different coverages of "sumanene" mlecules
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-<code> 
-wget  
  
-</code>+Please download the program **monte_carlo.py** from [[https://polybox.ethz.ch/index.php/s/CH5VdcI40YdELez|this link]]  
 + 
  
 </note> </note>
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 <note important> <note important>
 **TASK 1** **TASK 1**
-Execute the program with parameters:+Execute the program 
 +<code> 
 +python monte_carlo.py 
 +</code> 
 + with parameters:
  
 <code> <code>
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 n0 is the concentration of dimers in the case of zero interaction n0 is the concentration of dimers in the case of zero interaction
 nexp is the concentration of dimers found in the experiment nexp is the concentration of dimers found in the experiment
 +<note warning>warning
 To compute the concentration consider that at coverage 0.02, in the simulation, the total number of molecules is 50 To compute the concentration consider that at coverage 0.02, in the simulation, the total number of molecules is 50
 +</note>
 </note> </note>
  
-<note warning>+<note important>
 **TASK2** **TASK2**
 repeat the simulation using as DE your estimate. repeat the simulation using as DE your estimate.
 What do you get? What do you get?
 +</note> 
 +<note important>
 **TASK3** **TASK3**
-Repeat the simulation with coverage 0.1 and DE=-0.02 and DE=-0.1+Repeat the simulation with coverage 0.1 and DE=-0.02 then DE=-0.1
 Describe what you obtain. Describe what you obtain.
 Now try coverage=0.1 T=400 DE=-0.1 Now try coverage=0.1 T=400 DE=-0.1
 Comment the result Comment the result
 +</note>
  
 +<note important>
 **TASK4** **TASK4**
-have a look at the pyhton code, identify the main MC steps in the MAIN part of the code+have a look at the pyhton code, identify the outer loop,  
 +mainly responsible of plotting and statistics
  
 <code> <code>
-clusters_plot=[]+#### outer loop of the siulation
 for i in range(nouter): for i in range(nouter):
- +</code> 
-and also the section+and  then identify the inner loop where the Monte Carlo moves happen: 
 +<code> 
 +#### inner loop of 1000 steps 
 +</code> 
 +and 
 +<code>
  
 #### DECIDE whether to accept or not the move #### DECIDE whether to accept or not the move
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 </code> </code>
 </note> </note>
-<note warning> +<note important> 
-The most complex (and unefficient) sections of the code are the two functions+**TASK 5** The most complex (and unefficient) sections of the code are the two functions
 <code> <code>
 def allconnected(m,id,nx,ny) def allconnected(m,id,nx,ny)
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 </code> </code>
 which finds out all the molecules that are 1st neighbors to a given one. which finds out all the molecules that are 1st neighbors to a given one.
 +<note warning> 
 +To understand these sections you have to refer to the graph of the hexagonal lattice 
 +with the convention adopted for the coordinate system.
 The function "allconnected" is quite intuitive and inefficient. Can The function "allconnected" is quite intuitive and inefficient. Can
-you imagine roughly a more efficient function to perform the same task? +you imagine roughly a more efficient function to perform the same task? 
 +Just think how you would do the task of identifying, among a set of particles, the ones that are alone, the ones that form 
 +an isolated dimer and thr ones that form clusters. Google can help you :) (you do not have to find a solution)
 </note> </note>
-<note warning>+</note> 
 +<note important> 
 +**TASK 6**
 The code, at each step, moves a particle chosen randomly to a new site chosen randomly. The code, at each step, moves a particle chosen randomly to a new site chosen randomly.
 **Would it be correct to move all particles in a step? **Would it be correct to move all particles in a step?
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