Search results
Results from the WOW.Com Content Network
With this definition the dipole direction tends to align itself with an external electric field (and note that the electric flux lines produced by the charges of the dipole itself, which point from positive charge to negative charge, then tend to oppose the flux lines of the external field). Note that this sign convention is used in physics ...
A point (electric) dipole is the limit obtained by letting the separation tend to 0 while keeping the dipole moment fixed. The field of a point dipole has a particularly simple form, and the order-1 term in the multipole expansion is precisely the point dipole field.
The electric potential at any location, r, in a system of point charges is equal to the sum of the individual electric potentials due to every point charge in the system. This fact simplifies calculations significantly, because addition of potential (scalar) fields is much easier than addition of the electric (vector) fields.
Continuous charge distribution. The volume charge density ρ is the amount of charge per unit volume (cube), surface charge density σ is amount per unit surface area (circle) with outward unit normal n̂, d is the dipole moment between two point charges, the volume density of these is the polarization density P.
Many times in the use and calculation of electric and magnetic fields, the approach used first computes an associated potential: the electric potential, , for the electric field, and the magnetic vector potential, A, for the magnetic field. The electric potential is a scalar field, while the magnetic potential is a vector field.
The electron electric dipole moment d e is an intrinsic property of an electron such that the potential energy is linearly related to the strength of the electric field: U = − d e ⋅ E . {\displaystyle U=-\mathbf {d} _{\rm {e}}\cdot \mathbf {E} .}
Since the electric dipole moment is a vector (tensor of the first rank), the diagonal elements of the perturbation matrix V int vanish between states that have a definite parity. Atoms and molecules possessing inversion symmetry do not have a (permanent) dipole moment and hence do not show a linear Stark effect.
Figure 1: Definitions for the spherical multipole expansion. The electric potential due to a point charge located at ′ is given by = = + ′ ′ . where = | ′ | is the distance between the charge position and the observation point and is the angle between the vectors and ′.