Nuclear magnetic resonance dipole dipole interaction

In summary, the conversation discusses the interaction between two neutrons with spin magnetic moments. The magnetic field generated by one neutron can induce transitions in the other neutron, and this interaction is described by the dipole-dipole interaction. The speed at which the second neutron feels the magnetic field is the speed of light, and the changing magnetic field can induce transitions on a fixed neutron.
  • #1
xfshi2000
31
0
Hi all:
One system consists of two neutrons. both spin magnetic moments are 1/2. At a instant time, neutron 1 locates position 1 and neutron 2 is in position. As we know, spin magnetic moment is kind of dipole moment. They can generate magnetic field (not electric field). The interaction can be described by m1*m2/r^3. m1/m2 stand for spin magnetic moment of spin1 and spin2. My question is that:
1)How fast spin2 can "feel" the magenetic field generated by spin1 when spin1 keep changing position due to thermal fluctuation?

Because spin1 moves at all times, spin2 see a continual change of magnetic field.
2) Is the change of magnetic field inducing the transition on spin2 if spin2 is in a fixed position?

3) Is the interaction between change of magnetic field and spin2 magnetic moment still dipole dipole interaction?

thanks
xf
 
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  • #2
1)The speed at which spin2 feels the magnetic field generated by spin1 is the speed of light, since the magnetic field is a form of electromagnetic radiation. 2)Yes, the changing magnetic field could induce transitions on spin2 if it is in a fixed position. 3)Yes, the interaction between the changing magnetic field and spin2 magnetic moment is still dipole-dipole interaction.
 
  • #3


Hello xf,

Thank you for your question. The nuclear magnetic resonance dipole dipole interaction is a fundamental concept in the study of nuclear magnetic resonance (NMR) spectroscopy. It refers to the interaction between the nuclear spins of atoms in a magnetic field, and is crucial for understanding the behavior and properties of these spins.

To answer your first question, the speed at which spin2 "feels" the magnetic field generated by spin1 depends on the distance between the two spins and the strength of the magnetic field. The closer the two spins are, the faster the interaction will occur. However, even at larger distances, the interaction can still be relatively fast due to the strong magnetic fields involved in NMR experiments.

For your second question, the change in magnetic field can indeed induce a transition in spin2 if it is in a fixed position. This is known as spin relaxation and is an important phenomenon in NMR spectroscopy. The change in magnetic field can cause the spin to flip, resulting in a transition between energy levels.

Finally, to answer your third question, the interaction between the change in magnetic field and spin2 magnetic moment is still considered a dipole-dipole interaction. This is because the interaction is between two magnetic dipoles, even though one of the dipoles (spin1) is changing due to thermal fluctuations.

I hope this helps to clarify the concept of nuclear magnetic resonance dipole dipole interaction. If you have any further questions, please don't hesitate to ask. Thank you for your interest in this topic.
 

1. What is nuclear magnetic resonance (NMR) dipole-dipole interaction?

NMR dipole-dipole interaction is a phenomenon that occurs between nuclear spins in a molecule. It is caused by the interaction of the magnetic fields produced by the nuclear spins of neighboring atoms.

2. How does NMR dipole-dipole interaction affect the NMR spectrum?

NMR dipole-dipole interaction causes the splitting of NMR peaks in a spectrum. This splitting, known as the spin-spin coupling, provides information about the number of neighboring nuclei and their relative positions.

3. What factors influence the strength of NMR dipole-dipole interaction?

The strength of NMR dipole-dipole interaction depends on the distance between nuclei, the strength of the magnetic field, and the gyromagnetic ratio (a property of the nucleus).

4. Can NMR dipole-dipole interaction be used to determine molecular structure?

Yes, NMR dipole-dipole interaction can provide valuable information about the connectivity of atoms in a molecule. By analyzing the spin-spin coupling patterns, the relative positions of atoms can be determined.

5. How is NMR dipole-dipole interaction utilized in practical applications?

NMR dipole-dipole interaction is widely used in chemistry and biochemistry for structural analysis of molecules, as well as in medical imaging techniques like magnetic resonance imaging (MRI) to produce detailed images of tissues and organs.

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