Lennard-Jones Potential and Inert Gas atomic bonding
Element | epsilon
(10 -16 erg) |
sigma
(Angstrom) |
Experimental cohesive energy (eV/atom) | Experimental cohesive energy (kJ/mol) | Nearest neighbour distance (Angstrom) | Melting point (K) |
Ne | 50 | 2.74 | 0.02 | 1.88 | 3.13 | 24 |
Ar | 167 | 3.40 | 0.08 | 7.74 | 3.76 | 84 |
Kr | 225 | 3.65 | 0.116 | 11.2 | 4.01 | 117 |
Xe | 320 | 3.98 | 0.17 | 16.0 | 4.35 | 161 |
(1) Use the above epsilon and sigma values in the expression for the Lennard-Jones potential
(2) Find the cohesive energy and the equilibrium seperation distance between the atoms of the different elements [If using MATLAB you can use the max and find functions to obtain it from the figures]. Compare the numbers you obtain with the experimental values given in the above table.
(3) Use the experimentally obtained values of cohesive energy to estimate
the melting points of the different elements. Compare with the observed
melting points given above.