| T O P I C R E V I E W |
| CoreyUofS |
Posted - 06/21/2011 : 12:50:15 PM
Origin Ver. and Service Release (Select Help-->About Origin): 7.5
Operating System: Windows XP Professional
Hello,
I'm working with a spectrum that has two gaussian peaks. When I use the advance fitting tool it gives me the following data:
quote:
Data: SData_Absor
Model: Gauss
Equation: y=y0 + (A/(w*sqrt(PI/2)))*exp(-2*((x-xc)/w)^2)
Weighting:
y No weighting
Chi^2/DoF = 0.00002
R^2 = 0.99876
y0 -0.0006 +- 0.00019
xc1 24180.94485 +- 0.8721
w1 842.53435 +- 1.86169
A1 442.93433 +- 0.90827
xc2 25162.82595 +- 10.22823
w2 498.01928 +- 19.32544
A2 16.59963 +- 0.73356
Now when I integrate the two guassian peaks the fitting tool out puts I get this data:
quote:
Peak 1
Area------------Peak at---------Width-----------Height
439.62129-------24178.56081-----992.65028-------0.41885
Peak 2
Area------------Peak at---------Width-----------Height
13.29298--------25200.71365-----583.76082-------0.02568
My problem is, how come the w1 is not the same as the width for peak 1 and w2 is not the same as the width for peak 2?
I used my calculator to manually figure out the width and the values from integrating seem to be the correct ones. |
| 2 L A T E S T R E P L I E S (Newest First) |
| easwar |
Posted - 06/21/2011 : 4:30:21 PM
Hi,
In recent versions of Origin, we added feature of Derived Parameter, so one can define new parameters based on the fitting parameter values, and those will be reported in the results/report sheet. So for example, with Gaussian, FWHM is defined as a derived parameter. Users can add more derived parameters to built-in and user-defined functions.
Easwar
OriginLab |
| CoreyUofS |
Posted - 06/21/2011 : 1:16:50 PM
When I looked a bit closer I found w wasn't the width, it was about 0.849 the width since it was width times sigma.
Problem solved :) |
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