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A Dipole moment at the sub atomic level

  1. Oct 18, 2016 #1
    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 will happen depending on response time and the time it takes the force (Field) to travel within the atom (probably the speed of light). This leads to a very small shift (depending on the atom velocity) in electron clouds relative to the position of the nuclei (very similar to portability but without external electric field).
    My first simple estimation (classical approach) is that for 1m/sec the atom clouds shits in 10-18m.
    This would generates dipole moment of 10-5Debay (just for comparison H2O has 1.85Debay).
    1. Did someone consider such mechanism? (I need link or paper).
    2. Is it possible to measure such low dipole moment?
    3. Consider lattice of mole atoms then I expect this dipole moment to sum up to much more significant, isn't it?
  2. jcsd
  3. Oct 21, 2016 #2
    1. Yes. Otherwise known as the Van der Waals force. It can occur for neutral molecules/atoms alike. I'm sure you can look up papers or read the Wikipedia page.
    2. Yes, these measurements are often done. http://phys.org/news/2016-05-physicists-van-der-waals-individual.html
    3. As the above article states, that's why geckos can stick to surfaces so well. The van der waals forces sum up enough to enable that.
  4. Oct 21, 2016 #3
    Thank you Modestyking for your repay. I'm well aware of the Van der Waals forces. Please note that I was referring to a phenomenon that should increases with the velocity of the subject. As far as I know Van der Waals interactions are independent on molecule velocity. Namely you can have interactions even the molecules are standing still.
  5. Oct 21, 2016 #4


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    Staff: Mentor

    A dipole field would lead to a force on a charge in this field.

    Consider the same situation in the rest frame of the neutral atom, with a moving charge somewhere: no force. Therefore, no dipole moment.
  6. Oct 21, 2016 #5
    A simple Google search seemed to yield a few papers, one of which is here: https://www.researchgate.net/publication/231076123_Velocity_dependence_of_the_van_der_Waals_force_between_molecules [Broken]
    Last edited by a moderator: May 8, 2017
  7. Oct 22, 2016 #6


    Staff: Mentor

    This does not happen, and PF is not the place for personal theory development.

    Thread closed.
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