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neb31
1 Posts |
 Posted - 06/19/2016 : 9:43:01 PM
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Origin Ver. and Service Release (Select Help-->About Origin): originpro8
Operating System:windows 10
I am trying to do a user-defined exponential fitting using the Fitting Function Organizer. Whenever I try to do the fit it says the fit does not converge (error -207). I am fairly new to origin so it may be a simple error, but I have not been able to fix the problem.
Independent variable=Ep
Dependent variable=y
Parameters=Ect,h,k,t
Function: y = (1/(Ep*sqrt(4.0*pi*h*k*t)))*exp(-((Ect+h-Ep)^2.0)/(4.0*h*k*t))
k and t are known, I am trying to find Ect and h with the fitting. Any suggestions? |
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Shirley_GZ
China
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Posted - 06/20/2016 : 02:20:29 AM
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Hi,
The fitting function looks good to me.
The reason could be improper initial values and parameter constraints or wrong model, etc.
Could you try to adjust the constant values(k and t) and initial values for the parameters(Ect and h) according to the actual situation?
If still problem, please send us the opj file with source data and the FDF file(User-defined fitting function file) , also the constant values and initial values for parameters, via tech@originlab.com. Please also tell us the serial number of you Origin.
Thanks,
Shirley
Originlab Technical Service Team |
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Curve fitting