What are the units of the radial wavefunction in my FORTRAN code?

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SUMMARY

The discussion centers on the normalization of the radial wavefunction in a FORTRAN implementation for solving the Hydrogen atom's wavefunction. The user employs the Euler method and the backward Euler method to derive solutions, with the analytic solution given by u = (1/√π)(1/a₀)^(3/2)r*exp(-r/a₀). The user operates in natural units where h-bar = c = 1, leading to a Bohr radius of 0.26737 keV^-1. The confusion arises regarding the units of the radial wavefunction, specifically whether the units should be keV^(1/2) or keV^-1, as the normalization condition indicates that R(r) has units of r^-3.

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  • Understanding of quantum mechanics, specifically the Hydrogen atom wavefunctions.
  • Familiarity with numerical methods, particularly the Euler method and backward Euler method.
  • Knowledge of normalization conditions in quantum mechanics.
  • Experience with FORTRAN programming for scientific computations.
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Physicists, computational scientists, and students working on quantum mechanics simulations, particularly those implementing wavefunction solutions in FORTRAN.

peanutbutter
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I am solving the Hydrogen wavefunction using FORTRAN.
Now using the Euler method, I am given a solution to match which is given by u10(r) = 1.06r*exp(-3.74r) (where unl(r) = rRnl(r) in general) which says it has a normalisation chosen to match what i should get from my code.

Then I use the backwards Euler method getting a more accurate solution with a correct shape and a much larger amplitude. I then normalise this and plot it against the analytic solution given by
u = 1/pi^1/2*(1/ao)^3/2*r*exp(-r/a0) which is apparently also normalised.

I am working in natural units so h-bar = c = 1 and me = 511.7keV the electron mass, which implies that my Bohr radius = 0.26737keV^-1 and I am working in units of r given by keV^-1 also.

so this would imply that the units of u for the analytic solution must be keV^(1/2) however looking at the original equation shouldn't the units be keV^-1 as u = rR(r) where r has units keV^-1 and R(r) is dimensionless, I'm confused. Is my normalisation unit calculated in fortran supposed to have units like the analytic normalisation constant?

On my graphs should I just put no units? :S
Any suggestions would be appreciated, units of wavefunctions has always confused me.
 
Last edited:
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The radial part of the wave function is normalized according to
$$
\int_0^\infty R_{nl}(r) r^2 \, dr = 1
$$
which means that ##R_{nl}## has the same units as ##r^{-3}##.
 

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