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Thread: NMR-relationship between magnetic field and radio waves

  1. #1

    Default NMR-relationship between magnetic field and radio waves

    Anyone here familiar with the relationship of magnetic wave and radio wave?
    we know that proton are surrounded by the electron. This is known as sheilding and helps to reduce the external magnetic field felt by the proton.
    However, to alight the proton with a external magnetic field,putting it into reasonance condition.

    so..

    "Suppose you were using a radio frequency of 90 MHz, and you adjusted the size of the magnetic field so that an isolated proton was in the resonance condition."

    Why is radion frequency and magnetic field in play?
    Isn't one suppose to 'play' with the radio frequency to suit the size of the magnetic field?

    TIA!

  2. #2
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    Default Re: NMR-relationship between magnetic field and radio waves

    Quote Originally Posted by Giorgio View Post
    Anyone here familiar with the relationship of magnetic wave and radio wave?
    If you're talking about magnetic resonance, I am rather familiar with it. But I don't understand your question. Maybe you could ask someone with a better grasp of English to help you formulate it?

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    Default Re: NMR-relationship between magnetic field and radio waves

    i only know that radio waves are em waves....

  4. #4

    Default Re: NMR-relationship between magnetic field and radio waves

    Quote Originally Posted by LittleWolf View Post
    If you're talking about magnetic resonance, I am rather familiar with it. But I don't understand your question. Maybe you could ask someone with a better grasp of English to help you formulate it?

    Yes i am talking about magnetic reasonance
    Let's say a C-H bond and C-O bond. Both will require different amount of radio waves and magnetic field due to the sheilding of the electrons around the proton or rather hydrogen nucleus.
    I know that in the prescence of a magnetic field, the proton will be 'forced' to be aligned with the magnetic field,how strong the proton will feel the force of the magnetic field will depend on the number of elctrons surrounding it and the depending on the attachment of the hydrogen nucleus it is with.

    Ok so,we know that magnetic field will try to make the proton reasonate.
    So when does the radio wave in this case comes in?
    What is the relationship it has with the magnetic field?

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    Default Re: NMR-relationship between magnetic field and radio waves

    Quote Originally Posted by Giorgio View Post
    Yes i am talking about magnetic reasonance
    Let's say a C-H bond and C-O bond. Both will require different amount of radio waves and magnetic field due to the sheilding of the electrons around the proton or rather hydrogen nucleus.
    I know that in the prescence of a magnetic field, the proton will be 'forced' to be aligned with the magnetic field,how strong the proton will feel the force of the magnetic field will depend on the number of elctrons surrounding it and the depending on the attachment of the hydrogen nucleus it is with.

    Ok so,we know that magnetic field will try to make the proton reasonate.
    So when does the radio wave in this case comes in?
    What is the relationship it has with the magnetic field?
    The magnetic field splits the energy levels of the I_z=+/- 1/2 spin states of the proton (nuclear Zeeman effect), E=-mu_n*g*B*I_z (where g is the nuclear g-factor, mu_n the nuclear magneton, and I_z the spin component parallel to the magnetic field B). The quantum (photon) energy of the resonant radio wave corresponds to this energy splitting.

    Wikipedia has a nice introduction to NMR.

  6. #6

    Default Re: NMR-relationship between magnetic field and radio waves

    Quote Originally Posted by LittleWolf View Post
    The magnetic field splits the energy levels of the I_z=+/- 1/2 spin states of the proton (nuclear Zeeman effect), E=-mu_n*g*B*I_z (where g is the nuclear g-factor, mu_n the nuclear magneton, and I_z the spin component parallel to the magnetic field B). The quantum (photon) energy of the resonant radio wave corresponds to this energy splitting.

    Wikipedia has a nice introduction to NMR.

    I never get anything done with wiki...
    You qoute that from wiki?never answer question leh...
    I know the number of spin is dependant on whether the amount of proton and neutron are equal and etc...equal number will produce a different spin while odd number will produce another kind of spin.
    It's the relation between the radion wave and magnetic field that leaves me puzzle.

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    Default Re: NMR-relationship between magnetic field and radio waves

    Quote Originally Posted by Giorgio View Post
    It's the relation between the radion wave and magnetic field that leaves me puzzle.
    It is in my answer - the photon energy of the radio wave is resonant with the Zeeman splitting. (Btw, it it is "radio", not "radion".)

  8. #8

    Default Re: NMR-relationship between magnetic field and radio waves

    Quote Originally Posted by LittleWolf View Post
    It is in my answer - the photon energy of the radio wave is resonant with the Zeeman splitting. (Btw, it it is "radio", not "radion".)
    ok pais seh...

    I realise i misunderstood the english...
    "The energy needed to make this flip depends on the strength of the external magnetic field used, but is usually in the range of energies found in radio waves - at frequencies of about 60 - 100 MHz."
    It just means the magnetic field needed to flip a proton for alignment is in the range of energy found in radio wave....

    Thanks away!

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