Potential non-Coulombic Interaction: Lennard Jones potential

Potential non-Coulombic interaction -- The second thing thomas taught me is about potential. this should I have learned through rote (to forget the formula) hahaha :D

The third day at IBK thomas directly talk about potential, which is the point I was told to study the literature on the potential to be used. in addition, Thomas also told me which kind of potential good and bad. according to Thomas, there are three types of good potential for explaining non Coulombic interaction, namely the Lennard-Jones potential, buckingham and Morse. okay, we start from a potential Lennard Jones,

Lennard Jones potential is often written as an equation with a rank of 12 - 6. Lennard Jones potential equation form are as follows:

where r ^ 12 is a tribe repulsion and r ^ 6 is the pull rate. it can be understood that the distance is too close, the repulsion between two particles become larger so that the energy would be worth +, if the distance we raise the energy will go down until it reaches the minimum value at the most optimal distance, if we increase the distance continues , the graph of quick energy will move close to 0 up at a distance of infinity. nah, to facilitate the calculations we usually set the cut off at a distance of 5-8 angstroem so that the minimum size of a box of our simulations is 10 angstroem.

in real life, the relationship between two human beings are basically following the Lennard Jones equation, where in close proximity so that mutual repulsion, at great distances weak interaction energy so neglected and we need optimum distance. hmm, so naturally some of my friends who live LDR they usually break up in the middle of the road.

buckingham form second potential is a potential. where this form is a simplification of the equation Lennard Jones.

at a distance of interaction of low energy will be negative because of the coefficient C / r ^ 6 becomes very large, in line with the increase in the distance, then the value of the energy will find the number "optimal" and move it close to 0 at long distances. buckingham potential is often used in molecular dynamics simulations (to make it, I do not understand, hehehe).

Thomas taught third potential is a potential Morse. Morse potential shape of the curve is approximately equal to Lennard Jones. where the minimum energy will be obtained at a distance r = r_e. This potential also contains parts repulsion and attraction, together with the Lennard Jones as well.

Note: non Coulombic interaction is an interaction at close range because of the long distances in value moves closer to 0, the difference with Coulombic interaction.