130_notes.dvi

(Frankie) #1

and


ρ=


− 8 μE
̄h^2

r.

Theprinciple quantum numbernis an integer from 1 to infinity.


n= 1, 2 , 3 ,...

This principle quantum number is actually the sum of the radial quantum number plusℓplus 1.


n=nr+ℓ+ 1

and therefore, the total angular momentum quantum numberℓmust be less thann.


ℓ= 0, 1 , 2 ,...,n− 1

This unusual way of labeling the states comes about because a radial excitation has the same energy
as an angular excitation for Hydrogen. This is often referred to asanaccidental degeneracy.


16.1 The Radial Wavefunction Solutions


Defining theBohr radius


a 0 =
̄h
αmc

,

we can compute the radial wave functions (See section 16.3.2) Hereis a list of the first several radial
wave functionsRnℓ(r).


R 10 = 2

(

Z

a 0

)^32

e−Zr/a^0

R 21 =

1


3

(

Z

2 a 0

) 32 (

Zr
a 0

)

e−Zr/^2 a^0

R 20 = 2

(

Z

2 a 0

) 32 (

1 −

Zr
2 a 0

)

e−Zr/^2 a^0

R 32 =

2


2

27


5

(

Z

3 a 0

)^32 (

Zr
a 0

) 2

e−Zr/^3 a^0

R 31 =

4


2

3

(

Z

3 a 0

) 32 (

Zr
a 0

)(

1 −

Zr
6 a 0

)

e−Zr/^3 a^0

R 30 = 2

(

Z

3 a 0

) 32 (

1 −

2 Zr
3 a 0

+

2 (Zr)^2
27 a^20

)

e−Zr/^3 a^0

For a given principle quantum numbern,the largestℓradial wavefunction is given by


Rn,n− 1 ∝rn−^1 e−Zr/na^0
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