- #1
Nano-Passion
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Homework Statement
The potential energy of two atoms in a molecule can sometimes be approximated by the Morse function, where r is the distance between the two atoms and A, R, And positive constants with S<<R. Sketch this function for 0<r<∞...
##U(r) = A ( (e^{(R-r)/(S)}-1)^2 - 1) ##
This is just one part of the problem but it is the part bothering me so I'll leave out the rest of the problem. This should be an easy problem, as indicated by the (*).
The Attempt at a Solution
##U(r) = A ( (e^{(R-r)/(S)}-1)^2 - 1) ##
I rewrite ##e^{(R-r)S}## as ##e^{R/S-r/S}##
The only way I can think about graphing this is to ignore all other things except for ##e^{R/S-r/S}## and manipulating R/S
Since S<<R, ##R/S→∞##
But then that just gives me nonsense! What else can I do?
Expanding ##(e^{R/S-r/S})^2## does not help either. Ignoring all constants and values except for r does not help either because ##e^{R/S-r/S}## = e^-r which will give me the wrong sketch.
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