EasySpin forum

Dear Esayspin group,

I have some problems regarding the fitting of OH radical spectrum. The signal to noise of the data is not good, which can be due to the low concentration of the OH radical in our samples. I am not sure if the low-quality data will impact the fitting process, because with the code I wrote, the fitting did not work properly. I can only get a line at the end of the fitting. We use Bruker EPR, so the unit is G, and I have converted G to mT already.
Below are the attached code and DTA file.
Please help to correct the code.
Thanks!

best regards,
Jennifer

Dear Jennifer,
could you please also share the 02a.DSC file?
Both DTA and DSC files are read in together to access the data.

And before the simulation: Did you consider any means for removing the magnetic field offset? E.g. by a reference sample of known g-value such as DPPH. Otherwise the magnetic field offset will appear as a "g offset" in the simulation.
Best wishes!

Dear Daniel,

Thanks for your reply.
Here is the DSC file.

I didn't do a reference sample of known g value before the experiment. How can I make up for this g offset when doing the simulation?

Best regards,
Jennifer

Hi Jennifer,

I think a large part of your problem might have been the lack of baseline correction. Then fitting at low signal/noise is more difficult.
Perhaps the script attached gives you a better starting point and also shows you the g_offset that can result from residual magnetization of the electromagnet and is usually calibrated with a reference sample (such as commercially available DPPH radical powder) measured in the same session with the same field settings.
However, the hyperfine splitting you can extract here and that was actually very good already in your file.
Have a nice day!

Hi Daniel,

Thanks for your help and correction! It works well.

Best regards,
Jennifer