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jkjkjk
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I am just a tiny bit confused at what would happen if you shot an electron directly at an ion's (with no electrons like deutrium 2+...) nucleus? would it stop and if so why?
jkjkjk said:I am just a tiny bit confused at what would happen if you shot an electron directly at an ion's (with no electrons like deutrium 2+...) nucleus? would it stop and if so why?
DrChinese said:Welcome to PhysicsForums, jkjkjk!
You would see scattering between the electron and the nucleus. But there would not be "direct" contact in the sense that the electron "hits" the nucleus.
xts said:1. What do you mean by 'directly'?
2. The asnwer depend on energy (in centre of mass) of the shot.
For low energies the electron would just got scattered (deflected) and some radiation (mostly X and gamma-rays) will be generated. For bigger energies the whole zoo of particles and antiparticles will be created. There are large laboratories utilizing such collisions (e.g. HERA - Hadron-Electron Ring Accelerator at DESY, Hamburg, colliding electrons with protons, but also, in limited range, with deuterons and even heavy ions)
xts said:Well - what does it mean 'direct contact'?
Actually in most such cases electron passes through the nucleus (through the proton), and is just deflected (with some Bremsstrahlung radiation).
There is nothing which could stop it. (Except of very-very-very low chance of being absorbed by proton, and convert it to neutron, but - honestly - I don't know if such reaction got ever observed, and don't ask me to calculate its weak probability)
If it has high energy it may kick out one of the quarks of the nucleus - and that quark, leaving the proton, creates pairs of quark/antiquark, then you see the whole explosion of various mesons spreading out, and the proton gets converted to some possibly strange, or even heavier baryon.
And of course, we forgot about the simplest answer
If your electron has very low energy, and it is shot at an ion, it may be just captured by it to form back an atom - emitting photon to balance the energy.
ADDED:
And, one more reaction (seen quite often if available energy is sufficient): electron, passing by nucleus, may create a pair of electron/positron, muon/anti-muon, tau/anti-tau.
jkjkjk said:////
That is what I don't really understand why wouldn't there be direct contact.
Yes, they can. Actually, scattering electrons is a good way to analyse internal structure of the nucleus (the same way as 100 years ago lord Rutherford analysed the structure of atom: http://en.wikipedia.org/wiki/Rutherford_scattering). Using higher and higher energies of electrons you may discover smaller and smaller details. First you may find, that nucleus is not a point, but it occupies some space - it may be seen as an uniformly charged sphere of the diameter [itex]\sqrt[3]{A}\cdot 2.5\cdot 10^{-15} {\rm m}[/itex]jkjkjk said:I didn't realize that it could pass through the nucleus
DrChinese said:Quantum particles - such as an electron - do not have a size in the classical sense of the word. Electrons behave much as point particles, in fact, meaning they occupy no volume. However, electrons are charged, and this creates interactions with other charged particles. Despite what you might expect, a negatively charged electron is not so attracted to a positively charge nucleus that they will "touch". At a certain point, they don't want to get any closer. This is a gross oversimplification, but that is the essential answer.
jkjkjk said:I have just realize that this sort of thread has been done to death and I am sorry about that
DrChinese said:No problemo! I would encourage you to read up some more and come back with more questions. It is a fascinating world we live in!
ZapperZ posted a nice FAQ here which addresses the area covered in this thread in a little more detail, check it out:
https://www.physicsforums.com/showthread.php?t=511179
Why Don’t Electrons Crash Into The Nucleus In Atoms?
When an electron is shot at an ion's nucleus, the electron will either be captured by the ion or it will continue on its path. If the electron is captured, the ion will become a neutral atom. If the electron continues on its path, it will collide with the nucleus and cause it to become ionized.
The impact of shooting an electron at an ion's nucleus is that it can change the charge of the ion. If the electron is captured, the ion will become neutral. If the electron causes the nucleus to become ionized, the ion will have a higher positive charge.
The outcome of shooting an electron at an ion's nucleus is influenced by the speed and direction of the electron, as well as the charge and size of the ion's nucleus. The energy of the electron also plays a role in the outcome.
Shooting an electron at an ion's nucleus has a variety of potential applications in fields such as nuclear physics, astrophysics, and materials science. It can be used to study the structure of atoms and ions, as well as to create new materials with specific properties.
When conducting experiments involving shooting an electron at an ion's nucleus, it is important to follow proper safety protocols and wear appropriate protective gear. This includes wearing gloves, safety goggles, and lab coats. It is also important to carefully handle and dispose of any radioactive materials used in the experiment.