L-J Potential-Distance of equilibrium

  • Thread starter Thread starter Pahoo
  • Start date Start date
  • Tags Tags
    Equilibrium
Click For Summary

Homework Help Overview

The discussion revolves around finding the distance of equilibrium for the Lennard-Jones potential, represented by the equation Uvdw(r) = -A/r^6 + B/r^12, with specific values for A and B provided. Participants are exploring how to determine the equilibrium distance based on this potential function.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants are attempting to understand how to calculate the equilibrium distance, with some expressing confusion about the process. One participant suggests a potential relationship involving r, while another questions how to find the minimum of the potential function.

Discussion Status

There is an ongoing exploration of methods to find the equilibrium distance, with some participants sharing their thoughts on potential calculations. While one participant claims to have figured out a formula for the minimum, there is no explicit consensus on its correctness, and further verification seems necessary.

Contextual Notes

Some participants mention a reference article that may provide additional context, and there is a suggestion to move the discussion to a different forum, indicating a potential mismatch in the topic's complexity.

Pahoo
Messages
7
Reaction score
0
LJ-Potential

Homework Statement


Find distance of equilibrium for:
1.
Uvdw(r)=-A/r6+B/r12
A=10-77 Jm6
B=10-134 Jm12



Homework Equations



Uvdw(r)=-A/r6+B/r12

The Attempt at a Solution


It is suppose that r is the distance, but I have not any idea how to calculate this.

appreciate your help
 
Physics news on Phys.org
Pahoo said:

Homework Statement


Find distance of equilibrium for:
1.
Uvdw(r)=-A/r6+B/r12
A=10-77 Jm6
B=10-134 Jm12



Homework Equations



Uvdw(r)=-A/r6+B/r12

The Attempt at a Solution


It is suppose that r is the distance, but I have not any idea how to calculate this.

appreciate your help

This article may help: http://en.wikipedia.org/wiki/Lennard-Jones_potential

This isn't really an engineering question, though. Would you like me to move this to the HH/Advanced Physics forum?
 

Homework Statement


Find distance of equilibrium for:
1.
Uvdw(r)=-A/r6+B/r12
A=10-77 Jm6
B=10-134 Jm12

Homework Equations



Uvdw(r)=-A/r6+B/r12

The Attempt at a Solution


It is suppose that r is the distance, I suppose that r=(2A/B)(1/6)
and 0=2A-Br6.
However I`m totally lost

appreciate your help
 
Last edited:
Thanks
 
The equilibrium distance is the minimum of the potential. How do you find a minimum?
 
ok, finally I figure out how to calculate the minimun which is r = (2^(1/6) B^(1/6))/A^(1/6). Am I right?
 
Looks good. I would express it as ##\displaystyle \left(\frac{2B}{A}\right)^{\frac{1}{6}}##
 

Similar threads

Replies
4
Views
4K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 17 ·
Replies
17
Views
4K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 21 ·
Replies
21
Views
2K
  • · Replies 9 ·
Replies
9
Views
5K
Replies
4
Views
2K
Replies
3
Views
3K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K