The Naked Scientists

The Naked Scientists Forum

Author Topic: Quantum Leap  (Read 4137 times)

Offline sohail

  • Jr. Member
  • **
  • Posts: 23
    • View Profile
Quantum Leap
« on: 08/09/2007 21:37:56 »
eeek, my first post! Well anywho, I heard that the phrase quantum leap comes from the fact that when an electron that's orbiting an atom strays out of its energy level it disappears and then reappears when it re-enters its energy level. Is this true? And if so what happens to it when it is gone? Are there any theories regarding this? If an electron is in the middle of a leap are there any signs it leaves? Does the charge on the atom change?


 

Offline DoctorBeaver

  • Naked Science Forum GOD!
  • *******
  • Posts: 12656
  • Thanked: 3 times
  • A stitch in time would have confused Einstein.
    • View Profile
Quantum Leap
« Reply #1 on: 09/09/2007 08:05:17 »
Hello Sohail, & welcome to TNS.

I don't think electrons can just "stray" out of orbit. There are certain mechanisms by which they can move/be moved into a different orbit, or leave an atom completely, & these both involve the release or absorption of energy (a photon is emitted or absorbed).

Electrons cannot just disappear as such - that would violate the conservation of energy. I seem to recall that they can be changed into other particles by some quantum process, but I can't remember the details.

In addition, Quantum Field Theory (I think) states that the vacuum is not empty. Particle/antiparticle pairs are constantly being created & destroyed. Such a pair could be an electron & a positron which will annihilate each other.

The charge on the atom will not change if the electron is switched into a different orbit; but, as the electron has a negative charge, losing 1 will cause a decrease in the negative charge of the atom.

I dare say soulsurfer, lightarrow, or someone of that ilk will drop in & give you a more detailed reply.
 

Offline sohail

  • Jr. Member
  • **
  • Posts: 23
    • View Profile
Quantum Leap
« Reply #2 on: 09/09/2007 11:28:51 »
Thanks, I think I have got my ideas muddled. The phrase comes from the fact that when an electron changes an energy or "quantum" level the switch is discontinuous when it is expected to be continuous. This is probably accounted for because energy comes in "lumps"?

Also, maybe if a electron goes up a quantum energy level then surely the fact that the electron is further away from the atom means that when for instance a negatively charged particle approaches it it will be slightly more repelled than if the electron was in a lesser more distant energy level.
 

Offline DoctorBeaver

  • Naked Science Forum GOD!
  • *******
  • Posts: 12656
  • Thanked: 3 times
  • A stitch in time would have confused Einstein.
    • View Profile
Quantum Leap
« Reply #3 on: 09/09/2007 16:20:05 »
I'm going to take the coward's way out & wait for a particle expert to answer that.  [:I]
 

Offline lightarrow

  • Neilep Level Member
  • ******
  • Posts: 4586
  • Thanked: 7 times
    • View Profile
Quantum Leap
« Reply #4 on: 09/09/2007 19:26:49 »
eeek, my first post! Well anywho, I heard that the phrase quantum leap comes from the fact that when an electron that's orbiting an atom strays out of its energy level it disappears and then reappears when it re-enters its energy level. Is this true? And if so what happens to it when it is gone? Are there any theories regarding this? If an electron is in the middle of a leap are there any signs it leaves? Does the charge on the atom change?
Probably what you heard is this: if an electron is in a specific atomic orbital, let's say 1s in the hydrogen atom, and then the electron is excited and goes to the orbital 2s, since from the two orbitals there is a region of space forbidden by the electron, in a sense it "disappears" from the first orbital to "reappear" in the second.
But you have to realize that electrons (at least inside atoms) are not point particles.
 

Offline lightarrow

  • Neilep Level Member
  • ******
  • Posts: 4586
  • Thanked: 7 times
    • View Profile
Quantum Leap
« Reply #5 on: 09/09/2007 19:40:43 »
Thanks, I think I have got my ideas muddled. The phrase comes from the fact that when an electron changes an energy or "quantum" level the switch is discontinuous when it is expected to be continuous. This is probably accounted for because energy comes in "lumps"?
We could be say yes, but from very far away: the fact energy comes in "lumps" is one of the things which affect the way we describe and compute microscopic systems (this way is Quantum Mechanics), from which we get specific orbitals for the electrons in an atom.
Quote
Also, maybe if a electron goes up a quantum energy level then surely the fact that the electron is further away from the atom
If an electron goes up to an higher energy level, it doesn't always go to an orbital which has greater distance from the nucleus with respect to the first orbital; the electron's energy doesn't depend on this distance only.
Quote
means that when for instance a negatively charged particle approaches it it will be slightly more repelled than if the electron was in a lesser more distant energy level.
The possibility for a negative charge approaching the atom to interact with the outer electron, given a fixed distance from the nucleus and the particle's trajectory, does certainly depend on the outer's electron's orbital distance and shape.
 

Offline DoctorBeaver

  • Naked Science Forum GOD!
  • *******
  • Posts: 12656
  • Thanked: 3 times
  • A stitch in time would have confused Einstein.
    • View Profile
Quantum Leap
« Reply #6 on: 09/09/2007 20:10:43 »
Our erudite Italian friend to the rescue!  :)

Grazie, lightarrow.
 

lyner

  • Guest
Quantum Leap
« Reply #7 on: 10/09/2007 13:43:42 »
The idea of quantum Physics had to be introduced because, when an electron accelerates, in classical terms, energy is transferred. An electron 'in orbit' around a nucleus is constantly being accelerated (changing direction all the time) so, in classical terms, it would lose energy and spiral into the nucleus.
To explain how this doesn't happen the electron was considered to have a wavelike nature and the new model  explains how it couldn't spiral in or out - it had to behave like a standing wave on a string.  A vibrating string can have one wave, two waves, or more, on it but the waves have to be complete waves (the so-called overtones / harmonics of the string). You can stimulate the string only to resonate at these frequencies. In the same way, you can only add electromagnetic energy at certain frequencies in order to make the electron change its energy from one level (state) to another permitted state or wave pattern around the nucleus. So the system can only accept or release energy in discrete dollops - or Quanta. The energy of these quanta is the same for all atoms of the same element and correspond to 'characteristic' wavelengths of the substance.
 

Offline lightarrow

  • Neilep Level Member
  • ******
  • Posts: 4586
  • Thanked: 7 times
    • View Profile
Quantum Leap
« Reply #8 on: 10/09/2007 15:22:24 »
Our erudite Italian friend to the rescue!  :)

Grazie, lightarrow.
Prego, DoctorBeaver!
 

The Naked Scientists Forum

Quantum Leap
« Reply #8 on: 10/09/2007 15:22:24 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums
 
Login
Login with username, password and session length