What is Dipole moment: Definition and 216 Discussions
The electric dipole moment is a measure of the separation of positive and negative electrical charges within a system, that is, a measure of the system's overall polarity. The SI units for electric dipole moment are coulomb-meter (C⋅m); however, a commonly used unit in atomic physics and chemistry is the debye (D).
Theoretically, an electric dipole is defined by the first-order term of the multipole expansion; it consists of two equal and opposite charges that are infinitesimally close together, although real dipoles have separated charge.
I have come up with a solution, however, I'm not sure whether I'm correct. A fellow student of mine has a different result. I'm gonna show my solution, and hopefully one of you can confirm my result or tell me what I did wrong.
$$
\begin{align}
p_z &= \int d^3x z \rho(\vec{x}) \notag \\
&=...
My thought: First of all, I find the upper hemisphere (with a total charge +Q): ##ρ(\vec r)=\frac {V} {Q}## where V is the volume of the upper hemisphere = ## \frac {2} {3} \pi R^3##. Secondly, find the lower hemisphere (with a total charge −Q): ##ρ(\vec r)=\frac {V} {Q}## where V is the volume...
Hi,
I would like to know why a particle with spin=0 can't posses a magnetic dipole moment?
Using Wigner-Eckart theorem for ##\langle j,1,m,0|j,m \rangle## I get ##\langle j'|| \vec{J}|| j \rangle = \hbar \sqrt{j(j+1)} \delta_{jj'}##
It seems like the right hand side is the magnetic dipole...
Hello! Assume I have a 2 level system, where the 2 levels have opposite parity. If I apply an electric field, I will get an induced dipole moment. For now I want to keep it general, so the induced dipole moment can be very large, too. Let's say that I start rotating this electric field in the...
How do I interpret physically what dipole moment is ? The explanations that I received were "two charges seperated by a small distance " ,"it talks about ability of a dipole to rotate under the influence of an Electric Field " ,"Second term of the Multipole expansion" ,I get that these terms...
If I have two separated and non-interacting molecules with different constants polarizabilities ##\alpha_1## and ##\alpha_2## and I send an EM field of frequency ##\omega## first on the molecule no.##1## and then on the molecule no.##2## so that the two molecules will have a dipole moment...
If I want to calculate the dipole moment of a dielectric cylinder of uniform polarization perpendicular to its axis, I could multiply the polarization by the volume of the cylinder, which is okay. But another method is to consider the cylinder to be a superposition of two cylinders of equal and...
Hey guys, I just numerically calculated the matrix elements for a superconducting qubit and I'm having some trouble to interpret the result.
I will include a plot of the matrix I got below:
I basically have "large" non zero elements on the main diagonal of this matrix. In previous courses I...
In a problem of an oscillating electric dipole, under appropriate conditions, one can find, for the potential vector calculated at the point ##\vec{r}##, the expression ##\vec{A}=\hat{k}\frac{\mu_0I_0d}{4\pi}\frac{cos(\omega(t-r/c))}{r}## where: ##\hat{k}## is the direction of the ##z-axis##...
In a problem of an oscillating electric dipole, under appropriate conditions, one can find, for the potential vector calculated at the point ##\vec{r}##, the expression ##\vec{A}=\hat{k}\frac{\mu_0I_0d}{4\pi}\frac{cos(\omega(t-r/c))}{r}## where: ##\hat{k}## is the direction of the ##z-axis##...
Hello!
I tried to solve a) see figure below, is it correct?
b) so what I think I can do is to solve ## M_{12} ## from the equation of the magnetic flux then I will get ## \frac{\Phi}{I} = M_{12}## Then I can even use the equation får the magnetic flux and the magnetic field $$ \Phi = \int \vec...
Hello! Are there any experimental measurements or theoretical calculations of the electric dipole moment of any Rydberg state for CaF or BaF? Thank you!
I could do the first part of the question with ease but second part I am not sure how to proceed. Should we calculate the magnetic field at d(where the loop is) and infer something from that for it's motion?? Plz help me out
Thanks in advance
On the first attached page ##\mu_z## is associated with orbital angular momentum (Eq. 41.34). On the following pages (Eq. 41.38) it is associated with spin angular momentum? Are these both part of the same thing? I tried to read further but the book does not address this. In example 41.6 it...
i recently read about the stern-gerlach experiment and found out that they did it in the first place to verify the principle of the "space quantization " introduced by Bohr , and they thought they did detect the quantization of the orbital angular momentum of ( L = 1 , m = 1,-1 ) neglecting the...
I have to estimate the electric dipole moment of an NV center in units of Am. I know that for a regular electric dipole moment it can be estimated using p=ed. With e=1.6*10^-19 and d=0.1 nm (interatomic distance), this however is in units Cm. I don't know how to go to Am
Summary:: What if you were calculating the voltage potential for a dipole, but underwater?
I'm making a predictive model (in R programming) for the voltage potential at any point around a dipole. I need to be able to change parameters, one being the k constant.
V=( kpcosѲ)/(r^2).
Where V is...
The equation that we saw in class is for a continuous charge distribution, I think that for this exercise I need to treat the system as a discrete charge distribution but I'm not sure. Also, I don't know how I can calculate the intensity of the electric field needed to move this charge.
Hello to everyone. The question or debate here is how you obtain the commonly known equation of dipole electric moment:
from the electrostatic potential equation for a multipole of order n:
I understand it is related with Dirac delta functions but a step by step solution might be helpful.Thank...
Summary: Why is the electric dipole moment of the nucleus of an atom equal zero?
Summary: Why is the electric dipole moment of the nucleus of an atom equal zero?
I read about the hyperfine interactions that cause the altering of the energy levels of the nuclues of an atom. Under the...
I am reading a PHD thesis online "A controlled quantum system of individual neutral atom" by Stefan Kuhr. In it on pg46, he has a Hamiltonian
I am also reading a book by L. Allen "optical resonance and two level atoms" in it on page 34 he starts with a Hamiltonian where the perturbation is...
Homework Statement
For a configuration of charges and currents confined within a volume ##V##, show that
$$\int_V \mathbf J d \tau = \frac {d \mathbf p}{dt}$$
where ##\mathbf p## is the total dipole moment.
Homework Equations
...
The Attempt at a Solution
I have one question: since the...
How to prove the dipole moment of an isolated quantum system in isotropic space is identically equal to zero, unless there exists an accidental degeneracy.
Thanks in advance
A bar magnet will have a definite magnetic dipole moment, irrespective of the presence of an external field. Why is the moment, then, always defined in relation to the torque it would feel in an external field? Is there any other definition for the same?
Homework Statement
Compare Dipole moment of CH3F and and CD3F where D is deuterium.
Homework Equations
Theory questions
The Attempt at a Solution
Our sir had explained that to do this question we muat take into account the vibration of the atom in the respective molecule.
That is that the...
Consider the magnetic field B generated by a magnetic dipole. The intensity of B measured along the
axis of the dipole, at a distance of 10 cm from the dipole itself, is 1.0 10-5 T. What is the size of the
magnetic dipole moment? (μ0 =4π10-7 mkg/C2)
a) 0.050 Am2
b) 5 10 -4 Am2
c) 0,1 Am2
d) 1 10...
Homework Statement
A plane z=0 is charged with density, changing periodically according to the law:
σ = σ° sin(αx) sin (βy)
where, σ°, α and β are constants.
We have to find the potential of this system of charges. Homework EquationsThe Attempt at a Solution
[/B]
I...
Homework Statement
This is from Griffith's Introduction to Electrodynamics, where the book is deriving the magnetic dipole moment from multipole expansion of the vector potential
The vector potential of a current loop can be written as
$$\mathbf{A(r)}=\frac{\mu_0 I}{4\pi} \left[ \frac{1}{r}...
When neutral atoms become polarized from ambient EM radiation, does this automatically imply that electrons have shifted orbitals,or do they remain in the same levels but become deformed? Thanks
When the aminoacid environment were changed with adding OH or etc., Aminoacid N terminal were affected by H amount and in determined pKa, they loose hydrogen from N terminal. NH3 goes Nh2. My question is related to this. While this event occur, how change dipole moment of this terminal? Electron...
The sources I've looked at claim the magnetic field is present because there are still some electrons in the neutron star.
Here is how I understand their reasoning: a star's radius significantly decreases when it collapses into a neutron star, ultimately decreasing its moment of inertia. In...
Homework Statement
A spherical shell of radius R has a surface charge distribution σ = k sinφ.
Calculate the dipole moment of the spherical shell.
Homework Equations
P[/B]' = ∫r' σ(r') da'
The Attempt at a Solution
So I believe my dipole will be directed along the y axis, as the function...
The Magnetic Dipole Moment for a Magnetic Field for a dipole oriented on the x-y axis is:
##\bar m = |m| \hat z##
The Magnetic Field is:
##\bar B = \frac{\mhu_0}{4 * \pi * |\bar r|^5} * 3 * \bar r * (\bar m . \bar r) - \bar m * |\bar r|^2##
Vector Potential is:
##\bar A = \frac{\mhu_0}{4 * \pi...
The think is that I would like to create a magnetic trap "minimum of magnetic potential energy in all 3 directions of space" using a distribution of magnetic dipoles as a field generator.
In other words, I would like to know if setting in some way some magnetic dipoles is possible to create a...
I was watching a video explaining how microwave ovens work when I found that there is a difference between my physics textbook and online images of the electric dipole moment of the water molecule, as well as the one shown in the video.
Why do they differ?
Lets suppose that I have a magnetic dipole moment at (0,0,0) pointing to the Z axis, and in the position (X,Y,Z) in the space, I have a Hydrogen atom, I would like to know the exact interaction between the magnetic field created by the magnetic dipole moment in (0,0,0) and the magnetic fields of...
Hi everybody,
I want to ask a question about the dipole moment vector ##\vec{d}##, with components expressed in the molecule-fixed axis. By permuting identical nuclei that compose a rigid molecule, I know how ##d_x##, ##d_y##, ##d_z## change.
But when dealing with non-rigid molecule, I no...
Homework Statement
We have an electric dipole with moment P=2*[10][/-5] pointing in x direction. What is the force experieced by dipole at origin when a point charge Q=3*[10][/-4] is located at (0.014 m ,0,0)
Homework Equations
1. [E][/dipole]=(1/4π[ε][/0])(2p/r3)
2. p=qs
3. F=qE
4. τ=pEsinϑ...
Homework Statement
I am given this picture
and I know that |q1|=2nC, |q2|=5nC, d=1mm
I need to first find the total dipole moment of the system. Then I need to find an equation that represents the electric potential due to this net dipole moment for all (everywhere)
Homework Equations
p=qd...
Homework Statement
Find the force of attraction between 2 magnetic dipoles a distance r apart. Both dipoles point to the right.
Homework EquationsThe Attempt at a Solution
All I need help with is figuring out how to determine if the force is attractive or repulsive between the 2 dipole...
The following mechanism leads me to wander that a moving neutral object (compose from atoms) in vacuum may generates electric filed due to very small dipole moment.
I propose that when atoms force to move in a certain direction the force propagates within the atom. A retardation in movements...
Is there any interaction between a perfect magnetic dipole and a perfect electric dipole, both at rest?
What abut real dipoles?
What does QED say about this?
Homework Statement
Hi everybody! I'm trying to solve a problem about dipoles, but there is something I don't quite get about it. Well, first here is the problem:
An electric dipole ##\vec{p}_1## is placed at the zero-point and shows in the z-direction. A second electric dipole ##\vec{p}_2##...
I was going through the chapter Chemical Bonding in one of the books and found something about orbital dipole due to lone pairs.
In each diagram the orbital dipole due to lone pair was directed from the central atom to the end of the hybridized orbital (lone pair).
Why is that so?
Im looking to find the resultant magnetic moment of a permanent magnet inside of a steel housing. Some of the remnant flux density is absorbed by the magnet and the field is altered. I want to figure out the total magnetic dipole including the presence of the steel housing. I've been using...