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## Solving Kramers- Kronig from absorbance: Difficulty in loess function

Hi,

I was to solve Kramers -Kronig relationship and find out the del n value. but the problem is it cant read the o matrix. here is the file attaced. Please help.

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## Re: Solving Kramers- Kronig from absorbance: Difficulty in loess function

 but the problem is it cant read the o matrix

What do you mean by that?

Did you create that sheet yourself and is the Excel file still in the same directory as the Mathcad file?

ad loess() is failing to converge: according to the help, span should be greater than 1/n, which in your case means span>0.014. You value of span is 0.002 and so is far too small. Increase the value of span accordingly and see if it helps. We cannot try as of the missing Excel file.

4 REPLIES 4

## Re: Solving Kramers- Kronig from absorbance: Difficulty in loess function

Please upload the excel worksheet containing the data.

## Re: Solving Kramers- Kronig from absorbance: Difficulty in loess function

 but the problem is it cant read the o matrix

What do you mean by that?

Did you create that sheet yourself and is the Excel file still in the same directory as the Mathcad file?

ad loess() is failing to converge: according to the help, span should be greater than 1/n, which in your case means span>0.014. You value of span is 0.002 and so is far too small. Increase the value of span accordingly and see if it helps. We cannot try as of the missing Excel file.

## Re: Solving Kramers- Kronig from absorbance: Difficulty in loess function

You need to increase span to 0.09. Your integral will still not work though, because you need to sort out your scaling for the limits. You are trying to force loess to extrapolate, which it can't do.

## Re: Solving Kramers- Kronig from absorbance: Difficulty in loess function

Hi Freinds,

Thank you for your kind replies.

here are the data file and the mathcad worksheet

I cant set the limits.So that it fails to converge.

Help