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Magnetic field of molecules

by anorred
Tags: field, magnetic, molecules
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anorred
#1
Dec12-13, 06:59 PM
P: 56
Do molecules have intrinsic magnetic fields to them? Lets say you have a water molecule H20. Would the oxygen have a field due to the orientation of it's electrons, and possibly the hydrogens fields act to reduce that field? I'm just curious.
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mesa
#2
Dec12-13, 07:17 PM
P: 515
Quote Quote by anorred View Post
Do molecules have intrinsic magnetic fields to them? Lets say you have a water molecule H20. Would the oxygen have a field due to the orientation of it's electrons, and possibly the hydrogens fields act to reduce that field? I'm just curious.
It changes depending on the movement and placement of the charges as far as the magnetic fields are concerned. When looking at water we are seeing the 'average' behavior of the interactions of these fields of a large group of likely very dynamic molecules.
anorred
#3
Dec12-13, 08:22 PM
P: 56
Well lets say you look at one water molecule. Does it have a magnetic field or does the random interaction of electrons cancel all magnetism out?

mesa
#4
Dec12-13, 08:46 PM
P: 515
Magnetic field of molecules

Quote Quote by anorred View Post
Well lets say you look at one water molecule. Does it have a magnetic field or does the random interaction of electrons cancel all magnetism out?
Once a magnetic field is generated from a moving charge it moves away at the speed of light as an EM wave so unless there is an exactly equal but opposite EM wave emanating at the same time then no.
DrDu
#5
Dec13-13, 03:38 AM
Sci Advisor
P: 3,564
There are molecules with a permanent magnetic moment. In most of them it is due to the spin of the electrons, e.g. in many transition metal compounds. There are a few were the orbital moment is responsible for part or all of the magnetic field like in nitrogen-monoxide or singulet oxygen.
Naty1
#6
Dec13-13, 08:23 AM
P: 5,632
Do molecules have intrinsic magnetic fields to them?
sure

Lets say you have a water molecule H20. Would the oxygen have a field due to the orientation of it's electrons, and possibly the hydrogens fields act to reduce that field? I'm just curious.

sort of, but better to understand the magnetic moments [field orientations] add as vectors;some examples here:


http://en.wikipedia.org/wiki/Magneti...agnetic_moment


Fundamental particles have intrinsic spin.....and an associated magnetic moment
check out

http://en.wikipedia.org/wiki/Electron_spin
mesa
#7
Dec13-13, 09:10 AM
P: 515
Quote Quote by DrDu View Post
There are molecules with a permanent magnetic moment. In most of them it is due to the spin of the electrons, e.g. in many transition metal compounds. There are a few were the orbital moment is responsible for part or all of the magnetic field like in nitrogen-monoxide or singulet oxygen.
Quote Quote by Naty1 View Post
sure




sort of, but better to understand the magnetic moments [field orientations] add as vectors;some examples here:


http://en.wikipedia.org/wiki/Magneti...agnetic_moment


Fundamental particles have intrinsic spin.....and an associated magentic moment
check out

http://en.wikipedia.org/wiki/Electron_spin
I was wondering when you guys were going to chime in.

Annored, this the the quantum mechanical view of how these molecules behave and is currently the best and most accepted model for the behavior of such structures. What I presented is the classical description which is typically only used for macro systems.

It's a wonderful part of science today and represents a split between two very different types of Physics as experiment shows it seems to 'change' when we zoom in for a closer look at atomic scales.
Naty1
#8
Dec13-13, 02:06 PM
P: 5,632
Anorred,
you can also some find interesting material in Wikipedia under

http://en.wikipedia.org/wiki/Polar_molecules

Note the first illustration, top right.....

And as you may know, microwave heating relies on
...polarized [water] molecules in the food to rotate and build up thermal energy in a process known as dielectric heating.
with a funny story here:

http://en.wikipedia.org/wiki/Microwa...ntal_discovery

It was in 1945 that the specific heating effect of a high-power microwave beam was discovered, accidentally. Percy Spencer, an American self-taught engineer from Howland, Maine who worked at the time for Raytheon was working on an active radar set when he noticed that a Mr. Goodbar he had in his pocket started to melt the radar had melted his chocolate bar with microwaves. The first food to be deliberately cooked with Spencer's microwave was popcorn, and the second was an egg, which exploded in the face of one of the experimenters.[6][7] To verify his finding, Spencer created a high density electromagnetic field by feeding microwave power from a magnetron into a metal box from which it had no way to escape. When food was placed in the box with the microwave energy, the temperature of the food rose rapidly.
I wonder how the candy melted before he did....


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