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| jorgek |
Posted - 03/16/2004 : 11:51:12 AM
Hi everybody!
I have fitted the same set of data using three functions: Voigt PsdVoigt2 and Psdvoigt1. Each one has it advantages, but in the case of the area results (which is important for me) I have found different results (without the error of each Fit, obviously).
This is very important for me. Even each Fit use different parameters they are clear except the so called mu value.
I would say, the problem is that I do not know the EXACTLY the meaning of the mu used in the PsdVoigt2 and Psdvoigt1 functions. Where I could find such information?
Thanks
Jorge
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| 1 L A T E S T R E P L I E S (Newest First) |
| easwar |
Posted - 03/17/2004 : 2:18:26 PM
quote:
I would say, the problem is that I do not know the EXACTLY the meaning of the mu used in the PsdVoigt2 and Psdvoigt1 functions. Where I could find such information.
Hi Jorge,
If you view the equation expression for these fitting functions in the NLSF Advacned Fitting Tool, (use Function->Select menu in NLSF, then pick PSDVoigt1/PSDVoigt2 and click on the Equation Radio Button), you will see:
So both PSDVoigt1 and PSDVoigt2 are just a summation of Lorentzian and Gaussian line shapes (as opposed to Voigt, which is a convolution of Lorentzian and Gaussian).
PSDVoigt1 uses a shared width parameter, w, for both Lorentzian and Gaussian.
PSDVoigt2 uses different width parameters, wL and wG, for Lorentzian and Gaussian respectively.
The parameter mu, as can be seen from the expressions above, decides what fraction of the contribution comes from the Lorentzian term and what fraction comes from the Gaussian term. The value of mu will therefore be in the range of 0 to 1.
Easwar
OriginLab.
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