Difference between revisions of "HCl Vibrational-Rotational Spectroscopy"

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===Spectral Analysis===
 
===Spectral Analysis===
 
:a) load IR data into Igor or Excel.
 
:a) load IR data into Igor or Excel.
:b) Use the cursor tool to tabulate the H<sup>35</sup>Cl and H<sup>37</sup>Cl data into separate columns.
+
:b) Use the cursor tool to tabulate the H<sup>35</sup>Cl and H<sup>37</sup>Cl data into separate columns,
:c) Note where the ''m=0'' forbidden transition should be.
+
:c) Assign an ''"m-value"'' to each transition, note where the ''m=0'' forbidden transition with the help of the following (click to make bigger).
 +
:[[File:Screen Shot 2020-03-26 at 8.48.29 AM.png|200px]]
 
:d)  
 
:d)  
  

Revision as of 13:49, 26 March 2020

Adapted from Experiment #38 (Shoemaker, Garland, Nibler, 1989)

See Chapter 8 (Engel), more will be presented in lecture...

Sample Preparation

a) Pull the HCl (g) off the headspace of a bottle of concentrated HCl using a 60 mL syringe.
b) deliver the HCl (g) to the gas-sampling IR cell.

IR Gas-Phase Data Collection

a) Collect data using the highest resolution.
b) average 32 scans (both background and sample)
c) Save-As...
(A complete set of data can be found here.)

Spectral Analysis

a) load IR data into Igor or Excel.
b) Use the cursor tool to tabulate the H35Cl and H37Cl data into separate columns,
c) Assign an "m-value" to each transition, note where the m=0 forbidden transition with the help of the following (click to make bigger).
Screen Shot 2020-03-26 at 8.48.29 AM.png
d)
https://en.wikipedia.org/wiki/Isotopes_of_chlorine
atomic masses in amu
Reduced mass, "mu" = (m1*m2)/(m1+m2)
1H 1.007825 amu (99.9885%)
35Cl 34.968853 amu (75.78%)
37Cl 36.965903 amu (24.22%)
conversion factor: 1.66054e-27 kg/amu

4) Plot "m" (x) vs the frequency (y) and fit to a second order polynomial.

5) The second order polynomial will take the form of equation 9 from (Exp 38, Shoemaker), hence you can determine alphae, and then of Be.

6) Using equation 5 and 3, then solve for "r" the average internuclear separation.