September 11, 2024, 01:43:05 AM
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### Topic: Spectroscopy  (Read 3688 times)

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#### NotSoSure

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##### Spectroscopy
« on: May 08, 2024, 02:43:17 PM »
hey I have tried to solve this:

The 12Carbon-14Nitrogen triple bond absorbs energy at 2150cm-1. How much shift do we expect in the peak of the Carbon-Nitrogen infrared spectrum, when we replace the 14Nitrogen atom with 15Nitrogen?

I did: ν=1/2π√k/μ => μ1=mC*mN(14)/mC+mN14 , μ2=mC*mN(15)/mC+mN15 then Δν=ν2-ν1. Is this correct?
I ask because it gives data: Avogadro constant (NA), Planck constant (h), (c) velocity and says k stays the same. I didn't use Avogadro constant anywhere..neither 2150cm-1. Any help? Thanks:)
« Last Edit: May 08, 2024, 03:06:31 PM by NotSoSure »

#### mjc123

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##### Re: Spectroscopy
« Reply #1 on: May 08, 2024, 04:53:06 PM »
You don't need the constants, all you need is the ratio of the reduced masses.

#### NotSoSure

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##### Re: Spectroscopy
« Reply #2 on: May 08, 2024, 07:33:24 PM »
Thank you for your reply! Is the way I solved it correct?

#### mjc123

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##### Re: Spectroscopy
« Reply #3 on: May 09, 2024, 05:18:04 PM »
You haven't solved it, but your approach is along the right lines.

#### NotSoSure

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##### Re: Spectroscopy
« Reply #4 on: May 09, 2024, 05:37:12 PM »
For masses I'll put mC=12 and m14N=14 , m15N=15 then replace the data given on those equations. Is there anything else I'm missing? Thank you for replying!!

#### sjb

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##### Re: Spectroscopy
« Reply #5 on: May 11, 2024, 12:22:10 PM »
m14N is not 14, and m15N  is not 15 if we are going to be picky (but probably won't make much difference)