What is the change of variables for Lennard-Jones potential?

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Homework Help Overview

The discussion revolves around the change of variables for the Lennard-Jones potential, a concept in molecular physics. Participants are exploring how to manipulate the potential formula using a new variable.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • One participant attempts to apply a unitless variable defined as X = r/σ to the Lennard-Jones potential but struggles to reach the expected proof. Others question the validity of simply changing variables without further clarification.

Discussion Status

The conversation is ongoing, with participants providing insights and seeking further elaboration on the change of variables. There is no consensus on the adequacy of the approach taken, and some participants are exploring the implications of the variable 'X'.

Contextual Notes

Participants are navigating the specifics of the Lennard-Jones potential and the implications of defining new variables, indicating a need for clarity on the definitions and meanings involved.

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Homework Statement


[PLAIN]http://img94.imageshack.us/img94/4287/len2.jpg

Homework Equations


[PLAIN]http://img710.imageshack.us/img710/2428/len1y.jpg


The Attempt at a Solution


I know my way around the Lennard-Jones potential formula, but this question stumps me.

Any clues on how to proceed are greatly thanked!
 
Last edited by a moderator:
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Just define a new unitless variable as X=r/\sigma.
 
nickjer said:
Just define a new unitless variable as X=r/\sigma.


I used your defined variable and plugged it in, but still cannot arrive at the proof given in the question, could you possibly expand further?

Thank you!
 
I wouldn't call that a proof. You are just doing a change of variables. You can replace r/\sigma with X in the above equation. Unless 'X' has a meaning that I am unaware of.
 

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