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 Fitting kinetics with Instrument Response		  New Topic  Reply to Topic
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Stuart_Archer

United Kingdom
1 Posts
Posted - 03/06/2017 :  09:26:32 AM  Show Profile  Edit Topic  Reply with Quote  View user's IP address  Delete Topic
Hi all,

I have a set of kinetic data from transient absorption which consists of a multiple exponential decay convoluted with a Gaussian instrument response function. We don't have a way of specifically measuring the instrument response with the equipment we have.

I have tried using the function described here:

http://www.originlab.com/doc/Tutorials/Fitting-Convolution

to fit my data, however this only seems to be appropriate for a single exponential function? I am not familiar with Origin C, is it simply a case of adding t1, t2, A1, A2 etc as extra variables in with the initial paramaters, or will this require a significant change to the code?

Alternatively, are there any built-in functions in Origin now that could deconvolute an instrument response with several exponentials?

Any help would be greatly appreciated!

Thanks :)

yuki_wu

896 Posts
Posted - 03/07/2017 :  02:23:24 AM  Show Profile  Edit Reply  Reply with Quote  View user's IP address  Delete Reply
Hi,

It is supposed that column A is sample data, column B is signal data and column C is an instrument response while your multiple exponential decay function is:


Now you can add extra parameters as needed for the two extra exponentials (ie, A2, t2, A3 and t3). You also need to change the exponential equation in code:

vSignal = A1 * exp( -t1*vSample ) + A2 * exp( -t2*vSample ) + A3 * exp( -t3*vSample );

Note that you should estimate the initial values for parameters before you perform fitting. Good initial values are the key to perform a perfect fitting with convolution.

Hope it helps.

Regards,
Yuki
OriginLab
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