Why does the PE becomes negative in potential energy versus intermolecular distance graph? [closed]








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In the potential energy versus inter molecular distance graph, we know that atoms/molecules/particles want to be at optimum distance from each other ie *$r\_0$* and to the left of this position in the graph, we get the repulsive force and to the right would be the attractive force acting between them.


Note: Inter-molecular distance is denoted by ‘r’.


However, I have the following questions regarding this graph:


Why does graph represent negative Potential energy after a certain inter-molecular distance ?


What does negative potential energy mean in this context since the repulsive energy at r=0 was positive?


What happens at the point when P.E. becomes zero for a certain inter-molecular distance?


If the P.E. at that point has already reached zero, why is there a further need to go into negative potential energy?
[![The graph itself](https://i.stack.imgur.com/jm5uO.png)](https://i.stack.imgur.com/jm5uO.png)


