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hjskofficial
10 Posts |
 Posted - 10/16/2024 : 09:53:32 AM
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Origin Ver. and Service Release (Select Help-->About Origin): 2018
Operating System: Windows 10
In my research, I frequently employ a self-defined Fano function to fit asymmetric line shapes. However, I often encounter confusion regarding the FWHM (w). The FWHM value reported by Origin software appears to deviate from the actual width measured at half maximum, particularly for line shapes with large Fano factors (q). For instance, this discrepancy is evident in the curve shown https://www.dropbox.com/scl/fi/wqqg4jriksr9ty6ctniqs/Question-of-FWHM-of-Fano-line-shape.opju?rlkey=5bu1xfpjoqlp6h60a4zxmhcmw&st=j5mnt9lb&dl=0. In addition, the w shown negative in this case. It is also confuse me. I'm seeking guidance on how to accurately determine and interpret the FWHM in these cases.
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Edited by - hjskofficial on 10/16/2024 09:54:59 AM |
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NicholasSupport
USA
41 Posts |
Posted - 10/16/2024 : 3:51:35 PM
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Hello Hong-Jhang,
The "w" parameter can be derived in different ways depending on the function, and it is not always equal to the FWHM. In these cases, it is still possible to define a Derived Parameter for FWHM.
In order to better address this case, can you share the self-defined Fano function you are using?
You can find this file (.fdf file extension) in the Origin User Folder > fitfunc.
You may also download the "OPJ Packer" app and use it to create a package containing your project file and fitting function. ( https://www.originlab.com/fileExchange/details.aspx?fid=438 )
I look forward to inspecting the fitting function file.
Best,
Nicholas G.
nicholas@originlab.com
OriginLab Technical Support Team |
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hjskofficial
10 Posts |
Posted - 10/17/2024 : 04:19:24 AM
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Hi Nicholas,
Thank you very much for the reply.
The self-defined Fano function is y=y0+H*(1+(x-xc)/(q*w))^2/(1+((x-xc)/w)^2), where y0 is offset; H is amplitude; xc is x center; q is a Fano parameter; w is x width.
quote:
Originally posted by NicholasSupport
Hello Hong-Jhang,
The "w" parameter can be derived in different ways depending on the function, and it is not always equal to the FWHM. In these cases, it is still possible to define a Derived Parameter for FWHM.
In order to better address this case, can you share the self-defined Fano function you are using?
You can find this file (.fdf file extension) in the Origin User Folder > fitfunc.
You may also download the "OPJ Packer" app and use it to create a package containing your project file and fitting function. ( https://www.originlab.com/fileExchange/details.aspx?fid=438 )
I look forward to inspecting the fitting function file.
Best,
Nicholas G.
nicholas@originlab.com
OriginLab Technical Support Team
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FWHM (w) of Fano function