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--- exercises_single_point_calculation_v2 [2015/02/06 14:03] – sclelia
+++ exercises:2015_ethz_mmm:single_point_calculation [2020/08/21 10:15] (current) – external edit 127.0.0.1
@@ Line 155: / Line 155: @@
 === 4. Step ===
-Here are reported the combiantion rules for pairs unlike pairs, i.e. for pairs of non identical atoms. \\
+Here are reported the combination rules for pairs unlike pairs, i.e. for pairs of non identical atoms. \\
 Once generated the ε and σ parameters for the couple Ar/Xe, generate once more the LJ dissociation curve. \\
 Compare the "mixed" curve to the two "pure" curves and report the position and depth of the minimum. \\
@@ Line 163: / Line 163: @@
 <note tip>
-Remember that you are running  with two different atom types. For this reason some of the input sections must be modified
+Remember that you are running  with two different atom types. For this reason some of the input sections must be duplicated for the two kinds of atoms present
 </note>
-  * The " LENNARD-JONES " section must deal with the non identical pair of atoms:
+  * The " LENNARD-JONES " section must be present for all the three possible couples: Ar-Ar, Xe-Xe and Xe-Ar.  Example:
 <code>
-      &LENNARD-JONES ! Lennard-Jones parameters
+      &LENNARD-JONES ! Lennard-Jones parameters for Ar-Ar interaction
+          atoms Ar Ar
+          EPSILON    [K_e] 119.8
+          SIGMA [angstrom]  3.401
+          RCUT  [angstrom]  25.0
+      &END LENNARD-JONES
+      &LENNARD-JONES ! Lennard-Jones Xe-Xe parameters
+           atoms Xe Xe
+           EPSILON    [K_e] 232
+           SIGMA [angstrom]  3.98
+           RCUT  [angstrom] 25.0
+       &END LENNARD-JONES
+      &LENNARD-JONES ! Lennard-Jones parameters for Ar-Xe interaction
           atoms Ar Xe
           EPSILON    [K_e] YOUR EPSILON
           SIGMA [angstrom]  YOUR SIGMA
           RCUT  [angstrom]  25.0
         &END LENNARD-JONES
 </code>
-  * The " CHARGE " section must be duplicated:
+  * The " CHARGE " section must be also duplicated:
 <code>
@@ Line 183: / Line 197: @@
          &END CHARGE
          &CHARGE
-          ATOM Ne
+          ATOM Ar
           CHARGE 0.0
          &END CHARGE
@@ Line 189: / Line 203: @@
 </code>
+===== Questions =====
+  * Sketch the LJ energy curve for the two set of parameters ($\sigma$ and $\epsilon$) provided.
+  * Report, for both curves, the minimum energy distance and the depth of the minimum.
+  * What are the major differences between the curves? How do they relate to the sets of parameters provided?