Keerthi posted an Question
July 04, 2020 • 00:48 am 30 points
  • IIT JAM
  • Chemistry (CY)

Question is in below attached photo

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    Priyanshu kumar best-answer

    https://drive.google.com/file/d/16godrcFIVFB1O6U33aWc69YyDR7p7xLi/view?usp=drivesdk keerthi go through this link...u get spectroscopy notes

  • Keerthi

    sir I couldn't able to understand the spectroscopy concept plz help me out in this

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    keerthi mainly spectroscopy technique is used to study the structure eluciditation of compound...you have heard about various techniques namely NMR, rotational ,vibrational,electronic,ESRetc...mainly these are all different because for this some electromagnetic radiation is needed to brought this technique viz infrared,visible,radio etc

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    like NMR gives signal where there is proton in conpound

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    IR Spectra gives ideas about the functional group....

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    so spectroscopy in simple words just say it is measurement of radiation

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    so for all these there is selection rule means that if selection rule is followed then transition occurs otherwise not....

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    All these spectroscopic techniques mainly based on absorption and emission of radiation but raman spectra is based on scattering of radiation...

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    thank you sir can you send selection rules pdf

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    😊

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    yes wait let me check...

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    okk sir

  • comment-profile-img>
    Priyanshu kumar

    keerthi read all the selection rules of all the spectroscopy and condition to show this spectra

  • comment-profile-img>
    Priyanshu kumar Best Answer

    option D is correct...see explanation In order for a molecule to display a pure rotational spectrum, it must have a permanent electric dipole. For a molecule to display a rotational Raman spectrum, its polarizability must anisotropic i.e. not be the same in all directions. Thus, O2, CO2, N2O will all fail to display a pure rotational spectrum. Although CH4 is non-polar, it does display a weak rotational spectrum because it distorts under the influence of centrifugal forces when rotating about one of the C-H bonds and becomes a symmetric rotor (see Section 2.6). All of the molecules on the list possess an anisotropic polarizability except CH4 and so the only pair of molecules to display both a pure rotational spectrum and a rotational Raman spectrum are NO and DCCH.

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