What is Dipole moment: Definition and 217 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.

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  1. A

    Calculating Dipole Moment of V2O5: What is the Value?

    What is the procedure to calculate the dipole moment value of a molecule? what is the dipole moment value of venadium pantoxide (V2O5)?
  2. I

    Electric Dipole Moment question

    Homework Statement Point charges +4.70 and -4.70 are separated by distance 3.90mm, forming an electric dipole. The charges are in a uniform electric field whose direction makes an angle 37.0 degrees with the line connecting the charges. What is the magnitude of this field if the torque exerted...
  3. facenian

    Magnetic dipole moment energy question

    Hello, I have this problem. I calculated the dipole energy of a dipole moment in an external field using the equation U_m=\frac{1}{2}\int\vec{A}\vec{J}dr^3=\frac{1}{2} \vec{\mu}.\vec{B} however when the force on a dipole is calculated using \int\vec{J}\times\vec{B}dr^3 the formula...
  4. M

    Proton electric dipole moment?

    Proton electric dipole moment... what's that all about?
  5. S

    Dipole moment of polarized sphere

    Homework Statement Consider a polarised sphere of radius R the polarization is given by P vector = (ar^2 + b) r hat = ( ar+ b/r) r vector Where a and b are constantHomework Equations Find the dipole moment of the sphere The Attempt at a Solution I knew that P (polarized)= delta p / delta...
  6. V

    Electric dipole moment in gaseous species.

    Homework Statement Consider the following species in the gaseous state: NF_3, \ BeF_2, \ BCl_3, \ KrF_4 \ and \ SeO^{2-}_4 . Which of them have electric dipole moment? Homework Equations The Attempt at a Solution I tried google, but I can't figure out how to check that..
  7. H

    Calculating Total Dipole Moment of Spherical Sheet

    Homework Statement A spherical sheet of radius a has surface-charge density which depends on the polar angle θ according to the formula σ(θ)=σ0+σ1cos(θ) Find the total dipole moment Homework Equations pz=∫(dQ)z z=rcosθ The Attempt at a Solution I calculated the 1st dipole...
  8. P

    Dipole moment and net torque of an atom

    Homework Statement The HCl (hydrochloric acid) molecule has a dipole moment of about 3.4x10-30 C.m. The two atoms are separated by about 1.10-10 m. What is the net charge on each atom? What is maximal torque that this dipole will experience in a 5.104 N/C electric field? How much energy one...
  9. N

    Different expressions for the dipole moment

    Hi In my book (Griffith's) there are two different expressions for the induced polarization, namely P = \frac{N}{\text{volume}}<d> where <d> is the average of the dipole operator and N the number of atoms. The other expression listed is P = \text{Re}[\varepsilon_0 \chi E] where E...
  10. M

    What is the dipole moment of this surface charge distribution?

    In the below figure, I'm supposed to express the z-coordinate of the point P, z', by the angle \theta Does this work out as z' = R\cdot \cos \theta? If so, I can't see why... Please give me a hint on this.
  11. S

    Find units of transition dipole moment

    I have been trying to figure out which formula for the relationship between oscillator strength and transition dipole moment is correct. Wiki had the following formula: http://photonicswiki.org/index.php?title=Transition_Dipole_Moment f = 4.703 \times 10^{29} \bar{v} \mu^{2}_{ge}\,\...
  12. D

    Dipole Moment, what is Q? and other questions

    Hello, I have some questions about Dipole Moment, taken from a General Chemistry textbook, in which they treat Dipole Moment as a scalar. Here is a worked example from this textbook: Homework Statement The dipole moment of HCl is 1.11 D, and the distance between atoms is 127 pm. What is...
  13. A

    What is the total dipole moment

    Sometimes I am asked to compute the total dipole moment of a charge configuration. Normally you work with dipole moment per unit volume, so you can find the above by integrating over the entire volume, which is quite easy. I'm curius though, what is the physical interpretation of the total...
  14. Saitama

    What Is the Dipole Moment of This Charge Configuration?

    Homework Statement 4 charges are placed each at a distance 'a' from origin. The dipole moment of the configuration is: a)2qa\hat{j} b)3qa\hat{j} c)2qa[\hat{i}+\hat{j}] d)none Homework Equations The Attempt at a Solution How do i determine dipole moment here when there is...
  15. T

    Differences between population lifetime and dipole moment lifetime

    Reading a book about atomic transitions i really don't understand physically what the book means when it talks about differences between the population lifetime and the dipole lifetime that appear in the coerence part of the density matrix of a 2 or a 3 level system. I imagine that the...
  16. T

    Understanding the Direction of Electric Dipole Moment Vector

    Hi friends as all know that the direction of electric dipole moment vector is from negative charge towards the positive charge. I am pretty confuse that this direction is allotted to the dipole moment vector with some reason or just by convention.
  17. Z

    Curl of the dipole moment vector - why is it not always zero

    I'm confused about what polarization of a dielectric does to its electrical properties. It is clear to me that polarization causes every little atom to get a tiny dipole moment. A measure of the polarization is therefore P = dipole moment per unit volume. However, what is really a dipole moment...
  18. H

    What Is the Dipole Moment of a Grounded Sphere in a Uniform Electric Field?

    Homework Statement The electric potential of a grounded conducting sphere of radius r in a uniform electric field E_{0}\hat{k}along the z direction is given by V(r,\theta )=-E_{0}r\cos \theta +\frac{E_{0}R^{3}\cos \theta }{r^{2}} where r is the distance from the centre of the sphere...
  19. I

    Electric Dipole Moment: Meaning & Significance

    What is the physical meaning of electri dipole moment? What does it tell us about the dipole? Please don't just throw away mathematical equation (p=qd r_hat); help me to get its physical sense!
  20. A

    Calculating Dipole Moment: 1.5uC at (0,3), (0,5)

    Homework Statement Determine the dipole moment for the following charge distributions: 1.5uC each at (0,3), (0,5), where the coordinates are in cm. Homework Equations p=qd The Attempt at a Solution Since the coordinates are (0,3) and (0,5) d is 2cm or 0.02m and q is 1.5uC or...
  21. J

    Magnetic Dipole Moment of an Electron

    Homework Statement I am so stuck on this, and would be very thankful for any help! a). Calculate the magnetic dipole moment of a single atom, based on the following model: One electron travels at speed 7.40 × 10^6 m/s in a circular orbit of diameter 2 × 10^-10 m. b). The individual atomic...
  22. L

    What is the dipole moment of 1,3,5-trichloro benzene based on the given data?

    Could anyone help me in solving this following problem. From the given data, i could calculate the dipole moments of all the disubstituted chlorobenzenes(o-, p- and m- isomers)..but i couldn't calculate the following...I would be thankful if anyone comes up with a needful explanation...thanks...
  23. L

    Calculating Electric Potential of Ammonia Molecule: Can You Help?

    Could anyone help me with the following problem? Ammonia molecule has a dipole moment of 1.47D. Calculate the potential generated by this molecule at a point on a dipole axis at a distance of 52.0 nm from the centre of the dipole. how large will the potential be if an ion of charge...
  24. J

    How Do You Calculate the Magnetic Moment of a Complex Wire Loop?

    Homework Statement A wire is bent into the shape shown in the figure. The semi-circular part has a radius r = 4.00 cm and the rectangular part has a width w = 1.00 cm. A current of 0.300 A runs through the loop. What is the magnitude of the magnetic moment of the loop? Note: The figure...
  25. I

    Dipole moment of a spherical shell

    Homework Statement I'm trying to do problem 3.28 in griffith's electrodynamics. The problem statement is, to find the dipole moment of a spherical shell with charge distribution σ = kcosθ The way I tried to do it was to use the definition of dipole moment, which griffith defines as P=...
  26. O

    What is Dipole Moment? - Experts Explain

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  27. C

    What is the average magnetic dipole moment?

    Though this might be absurd, I would seriously like to know the average magnetic dipole of a magnet. For example, you might consider a regular magnet in a remote control car's motors, or any other suggestions too. And I have one more doubt- I know that e.m.f=-d(phi)/dt and phi=integral(B.dS)...
  28. B

    Solving Two Point Charges: Electric Field, Dipole Moment & Potential Energy

    Homework Statement Two point charges q1 = 2\muC and q2 = -2\muC are placed at r1 = (3,0,0) m and r2 = (0,0,4)m respectively i) What is the force of q1 (in vector form)? ii) What is the electric field at the origin? iii) What is the electric dipole moment of this arrangement (in vector...
  29. O

    Einstein-de Haas Experiment: Magnetic Dipole Moment Alignment

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  30. D

    My neighbor's friend discovered the Neutron Dipole Moment

    Yeah it's true, I heard him talking all about it tonight. He said he came up with the theory for it a while ago and he heard of it recently then he knew he was right. Among other things, he briefly said he connected quantum mechanics and consciousness. Then to top it off he said physicists...
  31. Y

    Finding Dipole Moment: Solve Integral & Calculate \vec p

    Homework Statement Given a sphere radius R with surface charge density \rho_s=k\;cos\theta. Find the dipole moment \;\vec p. Homework Equations \vec p=\int \vec r'\rho_s \;d a = \int_0^{2\pi}\int_0^{\pi}\vec r' k\;cos\theta\; R^2d\theta\;d\phi The Attempt at a Solution To me, \vec r' =...
  32. A

    Magnetic dipole moment of a ferromagnetic cylinder

    I have a Nickel cylinder, 5 micron in diameter and 10 micron in length. I know the external field \vec{B} is 80 gauss, what is the formula for the magnetic dipole moment of this cylinder in the field? Now I only have the formula for magnetic dipole of spheres, which is \mu = \frac{4}{3}\pi...
  33. W

    Direction of electron's total magnetic dipole moment

    Hi, What direction does the electron's total magnetic dipole moment point relative to it's total angular momentum vector L+S? It seems to me that it would point oppositely to J=L+S since the spin magnetic dipole moment and the orbital magnetic dipole moment are both opposite to L and S, but...
  34. A

    Explain how an atom may have a permanent magnetic dipole moment

    Explain how an atom may have a permanent magnetic dipole moment? Many thanks...
  35. E

    Nonlinear optics: electric dipole moment operator

    I am participating in a reading course on nonlinear optics, which is a little difficult since I haven't had any formal education in quantum mechanics other than the standard introductory solving of Schroedinger's eqn. in 1D. Happily this course takes the semiclassical approach, in which the...
  36. J

    Neutron Dipole Moment: Parity & T-Symmetry Violation?

    I have been wondering recently about the neutron dipole moment, after looking it up with the limited things available on the internet (to my knowledge anyway :) ) I have a few questions hopefully someone could answer for me. Firstly of the three symmetries, as I understand it, Parity, Charge...
  37. J

    Neutron Dipole Moment: Parity, Time Reversal Symmetry

    Hi, I have been wondering about a neutron dipole moment, though hypothetical what symmetries would it be violating, wouldn't it be Parity and Time reversal? If this were to be true, would it therefore make the statement below false and the word "inverted" would imply parity? "T is the law of...
  38. S

    Exploring Dipole Moment of Halomethanes in Organic Chemistry

    I'm reading in my organic chemistry text about the structure of alkyl halides, as a background to why certain reactions happen (specifically radical halogenation). In it there's a table of halomethanes, that tells the bond length, bond strength, and dipole moment. It pretty much looks like...
  39. S

    Dipole Moment (D): Definition & Explanation

    Oops
  40. R

    Integral of electric field of dipole moment over a sphere at r = 0

    Homework Statement Can't get to the final equality ( integral = - 4*Pi/3). Homework Equations \int_V \mathbf{E }dV = - \int_F \frac{_{\mathbf{p}.\mathbf{e_{r}}}}{r^2}\mathbf{e_{r}}r^{2}d\Omega = \mathbf{p}\frac{-4\pi }{3} The Attempt at a Solution Can't find how to get -4Pi/3...
  41. Z

    Dipole Moment of Two Electrons

    Why is the dipole moment of two electrons equal to zero? \vec{d} = \sum{q_{i}\vec{r_{i}}} The distance between them is nonzero and they both have charges. It is not obvious to me why this sums to zero.
  42. C

    Touque and Work from a Dipole Moment

    Problem: A dipole consists of charges +q and -q separated by 0.62nm . It is in an electric field 2.6×104 C/N. What is the work required to rotate the dipole from being oriented parallel to the field to being antiparallel to the field? Equations: . 90...
  43. G

    Torque of electrical dipole moment

    Homework Statement Calculate each torque of a dipole rotating at 30 degree increments for 180 degrees. Dipole: s=.55 cm q=+/- 3.7nC Distance from point charge to axis of dipole = 14.3 cm point charge = +4.5 nC So there should be 8 phases and 7 torques (number 4 doesn't have a torque...
  44. T

    Calculate Electric Dipole Moment: Magnitude & Direction

    Hi,can anyone tell me how to calculute magnitude and direction of the electric dipole moment of a system? If the system is a bit complicated? What kind of formula I suppose to use? \vec{p}=q\vec{d}?
  45. P

    Magnitude of the electric dipole moment in semiconductors

    When using k.p theory to calculate the magnitude of the electric dipole moment in semiconductors for band-to-band transitions, the value of the dipole moment is basically fitted to the effective mass of the electron in the conduction band. However, the values turn out to be larger than the...
  46. G

    Electric & magnetic dipole moment

    Hello, I have doubts with this problem, I'm not sure, if my solutión is right, so, here we go Let's two equal charges with the same charge but opposite signs, positive and negative, in a circle, such a distance between them is constant and equal to diametre of the circle. Both charges, turn...
  47. S

    Dipole moment of sphere with uniform volume charge Q

    Homework Statement Determine the dipole moment, \mathbf{p}, of a sphere of radius R with a uniform volume charge, total Q, with respect to its center. Homework Equations \mathbf{p}=\int \mathbf{r} \rho(\mathbf{r}) d\tauThe Attempt at a Solution I know that \mathbf{p}=\mathbf{0}, but I have a...
  48. C

    Do Gluon's have a magnetic dipole moment ?

    Do Gluon's have a magnetic dipole moment ? I hope this is the right place to post this.
  49. A

    QCD theta angle and Neutron electric dipole moment

    Dear all I have done some studies trying to understand the relation between the QCD theta angle and neutron electric dipole moment. General, the QCD vacuum produces the term L_{\theta} = \theta g_s^2\: G_a^{\mu\nu} \, G^a_{\mu\nu} this I can derive! I have studied Srednicki ch 93, Ramond...
  50. N

    Elementary confusion about the magnetic dipole moment and field lines

    simple magnetic dipole moment with impossible field lines? clueless. Hello, I'm taking a first year university course in electromagnetism. At a certain point we came upon the torque on a current loop in a uniform magnetic field. There we introduced the magnetic dipole moment \overline{\mu} =...
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