Quantum Physics help/Electron trap problem

AI Thread Summary
The discussion revolves around calculating the ground state energy of a system containing seven electrons in a rectangular corral defined by dimensions Lx = L and Ly = 1.94L. The energy levels are derived from the equation Enx,ny = h^2/(8mL^2) (nx^2 + ny^2), with attempts made to identify the ground and excited states. The user expresses confusion about the energy states, particularly regarding the first excited state, which can have multiple configurations. They calculate the total energy based on the distribution of electrons across these states, leading to a total of 32 multiples, but are unsure how to adjust this for the rectangular shape of the trap. Clarification on how to account for the rectangular dimensions in energy calculations is sought.
clowe521
Messages
2
Reaction score
0

Homework Statement


A rectangular corral of widths Lx = L and Ly = 1.94L contains seven electrons. What multiple of h2/8mL2 gives the energy of the ground state of this system? Assume that the electrons do not interact with one another, and do not neglect spin.


Homework Equations


Enx,ny = h^2/(8mL^2) (nx^2 + ny^2)



The Attempt at a Solution


used (nx/Lx)^2 + (ny/Ly)^2 to solve for the energy states resulting in
ground state: 1.266
1st excited: 2.063 (or 2.266?)
2nd excited: 5.063

I feel this approach is incorrect because the 1st excited state could have two possible energy states...

obviously, after finding the states, I multiplied 2 electrons by ground, 4 by 1st, and 1 by second, but the sum jumps around the answer instead of giving me a correct answer.

I'm new to the forum posting, but you guys are always a big help for me so thanks for any input ahead of time.
 
Physics news on Phys.org
state energy
1,1 2
1,2 5
2,1 5
2,2 8

So won't the energy be 2*2 + 5*2 + 5*2 + 8*1 or 32 multiples?
 
Yes, there will be 32 multiples, but that would be assuming a square electron trap...I'm not sure how to figure out the multiples based on the trap being rectangular.
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top