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nanak
4 Posts |
 Posted - 04/07/2014 : 03:23:47 AM
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Origin Ver. 6 and Service Release (Select Help-->About Origin):
Operating System: Win 7
Hi,
A spectroscopic peak that I was trying to fit agrees well with a Voigt function. I found that there was a small shoulder to the data points which requires another Voigt. I could not use multiple curve option for Voigt (only Gauss and Lorentz) are available. So, I simply created a third term in the Voigt equation with another set of (peak centre, width, A etc) parameters. However, when I used the UserDefined function that I thus created, Origin does not fit it.
Can someone give me the proper code to do this with either Origin6 or Origin8?
Thanks in advance.
Nanak. |
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zahraa
USA
52 Posts |
Posted - 04/07/2014 : 10:52:21 AM
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Hi Nanak,
You can try using the Peak Analyzer.
Go to Analysis: Peaks and Baselines: Peak Analyzer: Open new Dialog.
- One first page select Fit Peaks and click Next
- Second Page click Next
- Third page click Next
- Fourth page, deselect the Enable Auto Find box and click the Add button. This will allow you to pick the peaks manually. Double click to select them then click Done. And then Next
- In the Fifth page click on the Fit Control button at the bottom. This will open a dialog, in the drop down from the bottom left, change the function from Guassian to Voigt. (Image below) You can then select the Fit until Converge button to see the results before clicking OK to exit this dialog and finally clicking Finish in the Peak Analyzer dialog.
This will give you the parameters for however many peaks you selected with the Voigt function.
PS: if you are using origin 8, you may have to update to the highest SR since they changed the Peak Analyzer design in one of the earlier Service Releases. You can so so here:
http://www.originlab.com/index.aspx?go=Support/ServiceReleases
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Edited by - zahraa on 04/07/2014 10:53:25 AM |
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nanak
4 Posts |
Posted - 04/08/2014 : 03:35:54 AM
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Hi Zahara, i figured out that i need to use the PseudoVoigt to fit multiple Voigt functions. Thanks for your help.
Nanak |
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Fitting multiple Voight to curve