Lennard Jones Potential & Kinetic Energy

AI Thread Summary
The discussion focuses on modeling two particle interactions using the Lennard-Jones potential, specifically addressing challenges in forcing the particles into the potential well. The user calculates a total energy of -6.0*10-20 by determining the kinetic energy needed based on the potential energy at a separation distance of 2.5*10-8. There is uncertainty about whether the energy requirements are interpreted correctly and if the kinetic energy calculations are accurate. Suggestions include starting one particle at zero velocity to simplify the model and considering an inertial frame for calculations. The user seeks clarification on energy interpretations and the effectiveness of their current approach.
relskhan
Messages
5
Reaction score
0
So I'm trying to model two particle interaction subject only to Lennard Jones potential. I have a specific potential I am using:
B3AADfbCIAEOi8o.jpg


My problem is forcing the two particles into the potential well. I have the particles at a separation distance of 2.5*10-8. The way I interpret this potential is that I can set a total energy of -6.0*10-20 by giving the particles a Kinetic Energy of 3.95*10-20 (Where Total Energy TE=KE + U or KE = TE - U => KE = -6.0*10-20 +9.95*10-20 = 3.95*10-20 , the -9.95*10-20 comes from U(2.5*10-8).

To set the kinetic energy I'm using 1/2 m (v12+v22). And giving particle 1 an initial velocity equal to some factor of particle 2's velocity.

Unfortunately, this is still not working. So I am either interpreting the different energy requirements on the diagram wrong - or not calculating the velocity for the KE correctly. Any ideas??
 
Physics news on Phys.org
How many dimensions? In dimensions higher than 1 you'll need a centrifugal term.

Actually, I'm not sure if this answers your question.
 
UVCatastrophe said:
How many dimensions? In dimensions higher than 1 you'll need a centrifugal term.

Actually, I'm not sure if this answers your question.
Good Point - I should have specified. This is all 1-D, I will 'upscale' to 3-D later, but for now, I just want the simplest model.
 
What isn't working about it? It might be easier to work out in an inertial frame where one particle has 0 velocity.
 
Calion said:
What isn't working about it? It might be easier to work out in an inertial frame where one particle has 0 velocity.
Well I didn't want to get into the details too far - I mostly want to make sure my interpretation of the Energies are correct. I could try starting the particle at 0 velocity - but - the potential will move it I'm sure.
 
I have recently been really interested in the derivation of Hamiltons Principle. On my research I found that with the term ##m \cdot \frac{d}{dt} (\frac{dr}{dt} \cdot \delta r) = 0## (1) one may derivate ##\delta \int (T - V) dt = 0## (2). The derivation itself I understood quiet good, but what I don't understand is where the equation (1) came from, because in my research it was just given and not derived from anywhere. Does anybody know where (1) comes from or why from it the...
Back
Top