Potential energy curve of a molecule

AI Thread Summary
The discussion centers on the relationship between potential energy and the distance between atoms, particularly regarding repulsion and attraction forces. When two atoms are brought closer than the equilibrium bond distance, potential energy increases, indicating repulsion. Conversely, as atoms approach each other near the equilibrium bond distance, potential energy decreases, reflecting attraction. The conversation highlights that while repulsion leads to an increase in energy when atoms are forced closer together, attraction results in a decrease in energy as they approach equilibrium. This duality is clarified with examples of charged particles, where separating two attracting charges increases the system's energy, while allowing them to come closer decreases it. The key takeaway is that the effects of attraction and repulsion on potential energy are context-dependent, influenced by whether the distance between atoms is increasing or decreasing.
freedom856
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Does anyone tell me why the potential energy increase(becomes more positive) when two atom put closer to each other which is smaller than the equilibrium bond distance while potential energy decrease(becomes more negative) when two atoms put closer to each other (which is close to equilibrium bond distance (faraway to equilibrium bond distance)

That is why repulsion causes energy increase and attraction causes energy decrease?

Thank you
 
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your question is itself being answered by yourself...:-p
 
i want to ask why repulsion will cause energy increase and attraction will causes energy decrease, Do you understand?
 
Potential energy is by definition minus the integral of force over distance, or force always points in the direction of decreasing potential energy.
 
freedom856 said:
i want to ask why repulsion will cause energy increase and attraction will causes energy decrease

This is not true as asked. Both can be seen as energy increase (decrease) depending on whether distance grows or goes down. As repulsion is opposite of attraction, nothing strange that effects are opposite when moving in the same direction.
 
Borek said:
This is not true as asked. Both can be seen as energy increase (decrease) depending on whether distance grows or goes down. As repulsion is opposite of attraction, nothing strange that effects are opposite when moving in the same direction.

can you give some example to me for what you said? thank you
 
If you have two different charges, they attract each other. Separating them means doing work on the system, and system energy increases. However, if you allow them to get closer, energy of the system decreases. So, you have a system of attracting charges, in one cases energy goes up, in other energy goes down. Clearly statement "attraction causes decrease of the system energy" is wrong.
 
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