Nuclear & Particle Physics - Spectroscopic Notation

In a ³S state of the helium atom, the possible values of the total electronic angular momentum quantum number are

A. 0 only
B. 1 only
C. 0 and 1 only
D. 0, 1/2, and 1
E. 0, 1, and 2

(GR9277 #31)

Solution:

Spectroscopic notation: N^2s+1 L_j=l+s

• N = the principal quantum number and will often be omitted
• s = the total spin quantum number
• L = the orbital angular momentum quantum number, l but is written as S, P, D, F, … for l = 0, 1, 2, 3,⋯
• j = the total angular momentum quantum number

For ³S 
S → l = 0
3 → 3 = 2s + 1 → s = 1
j = l + s = 0 + 1 = 1

Answer: B