[Wien] A simple question

[Stefaan Cottenier]

> I have a simple question about the unit of Kmax. When we choose
> Rmt*Kmax=7.0, and the smallest Rmt=2.0 bohr
> so Kmax=7/2=3.5,but What unit Kmax has? and the corresponding cutoff
> energy?

There are probably easier ways if you are used to think in atomic 
units, but I'd do this: Your Kmax of 3.5 quoted above is of course in 
inverse bohr, or in 1/0.529277 inverse Angstroms. Convert this to 
inverse meters, fill out in the equation hbar^2*Kmax^2/2m (using all 
SI units), and you get the cutoff energy in Joule. Then convert back 
to either eV or Ry, as you like.

Stefaan