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--- exercises:2018_ethz_mmm:lennard_jones_cluster_2018 [2018/02/23 08:37] – dpasserone
+++ exercises:2018_ethz_mmm:lennard_jones_cluster_2018 [2018/04/14 14:50] – replace pdf with doi link oschuett
@@ Line 22: / Line 22: @@
 In this exercise you will test the Lennard-Jones potential. In particular, we will focus on the system described in the following paper about the energy landscape of the 38 atom Lennard-Jones cluster:
-<note tip>{{ :exercises:2017_ethz_mmm:1999_the_double-funnel_energy_landscape_of_the_38-atom_lennard-jones_cluster.pdf |}}
+<note tip>[[doi>10.1063/1.478595]]
 </note>
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 <note important>NOTE ON THE UNITS: CP2K USES SO CALLED "atomic units". Meaning that the resulting energies are expressed in Hartree,
 **1 Hartree=27.2114 eV**.
-In the input file, the epsilon value (depth of the well) is expressed in KT units, namely, in "temperature" units (there is a Boltzmann constant to make units work...). **The sigma value is in Angstrom.**
+In the input file, the epsilon value (depth of the well) is expressed in KT units, namely, in "temperature" units (there is a Boltzmann constant K_b to make units work...). <code>1 Kelvin*K_b=3.2E-6 Hartree</code>. Using this conversion factor you can transform the epsilon value into Hartree, and the total energy can be expressed in units of epsilon.  **The sigma value is in Angstrom.**
 </note>
 <note tip>
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 <note tip>Assignment:
   - Report the energy of the minima, compare it with the ones of the initial configurations.
+  - After converting the energy into "epsilon" units, estimate the number of bonds in the cluster, assuming a pairwise interaction.
   - Plot q4 vs. energy and q4 vs. optimization steps, for the two cases. Discuss the results. Are the minima in two separate basins?
   - Report the value of the order parameter of the minumum, and discuss what you see