# Spin angular dipole momentum of the electrons

1. Sep 15, 2007

### yyouth24

do the electrons have spin angular dipole momentum? (In classical mechanics, the spin angular momentum of a body is associated with the rotation of the body around its own center of mass)

Thank you.

2. Sep 15, 2007

### Staff: Mentor

Electrons have an intrinsic angular momentum whose magnitude is $(\sqrt{3} / 2) \hbar$. This is often called "spin angular momentum" even though an electron cannot be considered as "spinning" in the classical sense (a small object physically rotating around its own axis, like the Earth's 24-hour rotation).

Intrinsic angular momentum is a quantum-mechanical property. It arises naturally in solving the Dirac equation (the relativistic analog of the Schrödinger equation).

3. Sep 15, 2007

### olgranpappy

whats with the factor of sqrt(3)?

4. Sep 16, 2007

### dextercioby

$$S^{2}|s,m_{s}\rangle =\frac{3}{4}\hbar^{2}|s,m_{s}\rangle$$.

Go figure...

The spin is a nonrelativistic property of quantum "elementary systems".

5. Sep 16, 2007

oh right.