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 = mv):
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;