Hi everyone,

I doing LCF on my XANES data. I wonder if someone can tell me the meaning of the values in parentheses following the weight value in the Fit results window?. I looked into the respective document section of the Manuel but could not find the answer, yet.

I am asking because I did a Fitting with over 20 standards (STD) to find all combination of max 4 standards which describe my unknown sample spectra. This results in a lot of combination with similar chi-square(reduced) and R-values. I know a relative changes between these values are more probably meaningful than absolute values.
A lot of the possible combinations provided by after the fit yieled combinations with at lest on STD having a weight of 0.000. (Fit 1). I thought that this would mean, that 3 standards are sufficient to describe the system. However, repeating the fit with only the three standards with weight > 0.0 yielded a complete different proportions (Fit 2).  How can this be explain and how should I deal with combinations or standards having  a weight of 0.000?

Thanks a lot for your thoughts and suggesting,

Cheers Paul

Results Fit  1:

  3: STD3           0.324(0.025)
  7: STD7             0.686(0.021)
  20:  STD2O       0.127(0.016)
  27: STD27         0.000(0.036)

vs.

Results Fit 2:
  3: STD3           0.473(0.019)
  7: STD7             0.620(0.023)
  20:  STD20       0.000(0.030)