Chapter
2

Chemistry 210

Quantum numbers, orbitals and energies

But something new occurs here: l is also involved in the radial wave equation (2.), which will place a new constraint upon the permissible values of l, and hence ml. We won't go through the tedious steps of solving the radial equation; it will suffice to look at the solutions, which can be found for energies

En =  Z2e4μ     n = 1, 2, 3, ...
8e02h2n2

(20.7)

In this equation Z is the charge on the nucleus, which is 1 for the hydrogen atom, 2 for the He+ ion, etc. The corresponding radial wavefunctions depend on both n and l, and are of the form

 
Rn, l (r) = ρlLn, l (ρ) e2     n = 1, 2, 3, ...,     l = 0, 1, 2, ..., n-1
 

where ρ is proportional to r

ρ =  2μ r
nmea0

and the constant a0 is known as the Bohr radius:

a0 =  4πε0ħ2 = ε0h2 = 0.529177 Å
mee2πmee2