-3

First let me stress the fact that this question is not a duplicate, there are many similar questions that have missed the point, in particular this

Why doesn't an electron ever hit (and stick on) a proton?

which was led astray by users who basically did not understand what had really been asked.

I'd like to make it clear that I am not looking for a theoretical explanation, but for a concrete description of what actually happens when a negative charge is released in presence of a positive one

enter image description here

if the positive particle is a positron the electron behaves according to Coulomb's law, if the particle is a proton or a nucleus the electron directs itself to the center of the proton and then deviates, I am asking a description of the process and if it is known what force makes the electron deflect from the normal trajectory.

All explanations given in other questions are irrelevant or wrong, like this by John Rennie:

Classically two pointlike particles, an electron and a quark, can never collide because if they're pointlike their frontal area is zero and you can't hit a target that has a zero area.

since a positronn, too, is a pointlike particle

Qmechanic
  • 201,751
user157860
  • 681
  • 3
    "I am not looking for a theoretical explanation, but for a concrete description of what actually happens". What do you mean by this? Physics is a scientific discipline in which one attempts to model reality, almost always with the use of mathematics. Are these models the "theoretical explanation" that you don't want? If so, what else is there? If you are okay with models, how many effects should an answer take into account? Only classical physics like Coulomb's law and Newton's laws? Quantum mechanics? Special relativity? Both the latter two, i.e. quantum field theory? – Marius Ladegård Meyer Feb 25 '22 at 12:19
  • Notice that even if we would like to, we simply cannot do an experiment where we track the path of an electron from the moment of release to "see what actually happens". This is because of the quantum nature of the electron. – Marius Ladegård Meyer Feb 25 '22 at 12:22
  • 2
    "since a positronn, too, is a pointlike particle", note, the quote says the same. Electrons and protons at distances of fermi are quamntum mechanical entities and no tracks can be predicted in quantum mechanics,, only probabilities given for a particular angle of approach. – anna v Feb 25 '22 at 12:28
  • 1
    Your premise is unsound. A free electron can approach a proton subject to an almost classical em attraction, and, if the "stars are right" lose enough energy to be trapped by the proton at about an angstrom's distance, to form a hydrogen atom. Is this the lies-to-children story you are pining for? – Cosmas Zachos Feb 25 '22 at 14:36
  • @MariusLadegårdMeyer, CosmasZachos, M his subject seems to be under a spell, all questions regarding the subject have been misunderstood and led astray. I am simply asking why an electron is attracted by an electron and sticks onto it whereas behaves differently if the positive charge is a proton or other. Is this so obscure and hard to understand? As to the theory I referred to answers that explained this invoking the uncertainty principle or other. Is it true that the behaviour is different?what makes this happen?Is this a bad, unsound question that deserves downvotes? O tempora... – user157860 Feb 26 '22 at 09:20
  • 1
    The subject is "not under a spell". You are getting answers, and if you are not able to understand or accept them, the fault is not with the answers. You seem to think that there is some super simple answer to your question, and that we are all bad at explaining this to you. But nature at the scale of electrons is not simple, or at least not intuitive. – Marius Ladegård Meyer Feb 26 '22 at 09:28
  • 1
    Also note that if an electron and positron meet, they don't actually "stick together" at all. They annihilate since they are antiparticles, and form pairs of photons. – Marius Ladegård Meyer Feb 26 '22 at 09:28
  • Spell? What spell? Clarify your question. It is elementary quantum mechanics. An electron is captured by a positron to form positronium, which then decays to photons. If captured by a proton, it forms a hydrogen atom, which is stable. Yet again, sharpen the point troubling you. If you 've got the gumption, appreciate the starting/ending energy of the electron: on the scale of an angstrom, 10 cm are infinity! – Cosmas Zachos Feb 27 '22 at 18:56
  • Are you asking why the hydrogen atom is stable but the positronium unstable? You *must* rewrite your question to clarify. – Cosmas Zachos Feb 27 '22 at 20:56

1 Answers1

0

In the image you provide,

+-

You have two oppositely charged centers at ten centimeters apart.

If the charge is carried by a solid mass, of dimensions up to $10^{-10}m$, an angstrom, composed of myriads of molecules the classical electrodynamics theory with the Coulomb potential predicts a direct attraction and neutralization , if they are at rest, a "sticking together once the two masses touch.This has not been falsified by experiments. A scattering track can also be predicted and observed with the classical theory.

There is a classical solution of planetary type orbits which has not been observed at the above dimensions because the experiment would be difficult in the gravitational field of the earth.

From ancient times people tried to imagine the smallest possible dimensions for matter. Atom comes from ancient greek philosophy,and it means "something that cannot be further cut", and in the last two centuries it became clear that at angstrom dimensions the classical electromagnetic theory could not work and a new one was needed.

The basic reason is that if the classical theory would extend to the dimensions of the atom , assuming a positive nucleus and a negative electron, the atoms could not exist with the classical theory. The electron would radiate and fall on the nucleus and no chemistry or spectra would exist. Instead there are stable atoms making up the chemistry of the world as we see it. See this answer of mine for a longer explanation and links.

The coulomb potential is used in quantum mechanics to derive the wavefunction of the system under study and it manages to predict the atomic observations where classical theory fails. In quantum mechanics the particles, electron and proton in your question, do not orbit around each other when near enough, but have orbitals, , stable solutions that give the probability of the electron to exist about the proton at an (x,y,z,t) point.

Observations at the angstrom dimensions have to depend on a theory, and the theory is validated and accepted if it can predict the data.

but for a concrete description of what actually happens when a negative charge is released in presence of a positive one

At the quantum dimensions, at low energies, when a positron hits an electron the two particles annihilate and create two photons. If they are energetic enough the energy can be transformed into numerous pairs of elementary particles, which has been studied with the LEP experiments for example.

anna v
  • 233,453
  • thanks for your effort, this subject seems to be under a spell, all questions regarding the subject have been misunderstood and led astray. I am simply asking why an electron is attracted by an electron and sticks onto it whereas behaves differently if the positive charge is a proton or other. Is this so obscure and hard to understand? As to the theory I referred to answers that explained this invoking the uncertainty principle or other – user157860 Feb 26 '22 at 09:16
  • @user157860 (you mean electron positron) the misunderstanding is yours, the attraction is the same, the same qm equation with the coulomb potential holds. In the case of e+ e- the bound state (positronium https://en.wikipedia.org/wiki/Positronium instead of hydrogen) disappears because the quantum numbers add up to zero, the electron cannot annihilate on the proton because the quantum numbers do not add up to zero allow it, – anna v Feb 26 '22 at 10:57
  • the electron has no baryonic quantum numbers and the proton noleptonic ones, so they cannot add up to zero and have to be stable Antiproton proton make for a little while a protonium, https://en.wikipedia.org/wiki/Protonium and then annihilate because the quantum numbers of the two add up to zero. – anna v Feb 26 '22 at 10:58
  • "...the electron has no baryonic quantum numbers and the proton noleptonic ones, so they cannot* add up to zero and have to be stable" You forget that an electron can* hit and stick to a proton in the electron capture. So the question boils down to "why can't this happen all the time? You did not explain that. Thanks anyway for you effort – user157860 Feb 26 '22 at 11:32
  • @user157860 it is very basic quantum mechanics. Until you study it you will be continually thinking in classical terms. Electron capture happens with a nucleus full of protons and neutrons for energy considerations , because the neutron is heavier than the proton, and an electron neutrino takes away the lepton number, and the neutron has the baryon numbers. https://en.wikipedia.org/wiki/Electron_capture . In electron proton scattering the electron shouldb energetic enough to reach the extra energy needed for the neutron – anna v Feb 26 '22 at 13:12
  • https://arxiv.org/abs/2006.08411 – anna v Feb 26 '22 at 13:21