orbital angular momentum جنباک ِ زاویهای ِ مداری jonbâk-e zâviyeyi-ye madâri
*Fr.: moment cinétique orbital, ~ angulaire ~*
1) *Mechanics*: The → *angular momentum*
associated with the motion of a particle about an origin, equal to the cross product
of the position vector (**r**) with the linear momentum (**p** = m**v**):
**L** = **r** x **p**. Although r and p are constantly changing
direction, L is a constant in the absence of any external force on the system.
Also known as *orbital momentum*.
2) *Quantum mechanics*: The → *angular momentum*
operator associated with the motion of a particle about an origin, equal to
the cross product of the position vector with the linear momentum, as opposed to the
→ *spin angular momentum*.
In quantum mechanics the orbital angular momentum is quantized. Its magnitude
is confined to discrete values given by the expression:
ħ &radic *l(l* + 1), where *l* is the orbital angular momentum quantum
number, or azimuthal quantum number, and is limited to positive integral values
(*l* = 0, 1, 2, ...). Moreover, the orientation of the direction of rotation is
quantized, as determined by the → *magnetic quantum number*.
Since the electron carries an electric charge, the circulation of electron constitutes
a current loop which generates a magnetic moment associated to the
orbital angular momentum. → *orbital*; → *angular*;
→ *momentum*. |