[Ifeffit] Fitting Commercial Molybdenum Disulfide

[dmc at pdx.edu]

Hi List,

     Here's my most recent data.  I was able to look at the individual paths 
and changed my R-range to 2-4.5 angstroms on the first set of data, I set the 
second set of data to the same range, although 4 works better as a maximum for 
that set.  The k-range on the second range had to be truncated though.  

Six paths are used for each fit, same parameters, except for amp (0.7 for one 
~0.8 for the other).  The seperate data sets still have a few parameters that 
are outside of the error bars of the other (ss2,ss3,ss4,alpha, alpha2,alpha5). 
What can I do to get these beamlines to agree? 

delr_#   define    alpha# * reff
all other parameters guessed.
ss for each path, only one e0 for all  

       Thanks for the help, Dan 


First Data set -- Full k-range works best, Full range used for fit.
Project title :  Fitting merge 10_15_04.chi

Guess parameters +/- uncertainties  (initial guess):
  e0   =     0.8686930   +/-    1.1038290    (guessed as 0.868694 (1.103841))
  ss   =    0.0041150   +/-     0.0004990    (guessed as 0.004115 (0.000499))
  ss2  =   0.0044360   +/-      0.0004450    (guessed as 0.004436 (0.000445))
  ss3  =    0.0243560   +/-     0.0201400    (guessed as 0.024368 (0.020159))
  ss4  =   -0.0065470   +/-     0.0047820    (guessed as -0.006545 (0.004786))
  ss5   =    -0.0016100   +/-   0.0050490    (guessed as -0.001611 (0.005047))
  ss6   =    0.0059980   +/-      0.0139390    (guessed as 0.005996 (0.013935))
  alpha =   -0.0011360   +/-      0.0029380    (guessed as -0.001136 (0.002938))
  alpha2 =    0.0071480   +/-     0.0019780    (guessed as 0.007148 (0.001978))
  alpha3 =    -0.0060900   +/-    0.0273580    (guessed as -0.006078 (0.027378))
  alpha4  =   -0.0198570   +/-    0.0154200    (guessed as -0.019851 (0.015430))
  alpha5  =    0.1399050   +/-     0.0148530    (guessed as 0.139906 (0.014848))
  alpha6  =    0.0199630   +/-     0.0268690    (guessed as 0.019961 (0.026862))

Def parameters:
  delr_1          =    -0.0051820
  delr_2          =     0.0326180
  delr_3          =    -0.0277930
  delr_4          =    -0.0906110
  delr_5          =     0.6384270
  delr_6          =     0.0910950

Set parameters:
  amp1            =  .7


Correlations between variables:
          e0 and alpha      -->  0.8170
          e0 and alpha2     -->  0.6726
          ss and ss2        -->  0.6591
       alpha and alpha2     -->  0.5516
      alpha5 and alpha6     --> -0.4856
          e0 and alpha3     -->  0.4083
      alpha3 and alpha4     -->  0.3588
         ss5 and ss6        --> -0.3581
       alpha and alpha3     -->  0.3100
      alpha2 and alpha3     -->  0.3045
         ss2 and alpha6     -->  0.2745
          e0 and ss3        -->  0.2649
          ss and ss3        -->  0.2627
         ss2 and ss3        -->  0.2626
         ss6 and alpha5     --> -0.2510
All other correlations are below 0.25











Second Data Set -- Trucated k-range (2-13.5) 
Project title :  Fitting merge 10_15_04.chi

Independent points          =      25.270507813
Number of variables         =      14.000000000
Chi-square                  =    1202.598221935
Reduced Chi-square          =     106.703108852
R-factor                    =       0.057229121
Measurement uncertainty (k) =       0.000827712
Measurement uncertainty (R) =       0.022111003
Number of data sets         =       1.000000000


Guess parameters +/- uncertainties  (initial guess):
  amp  =   0.7976070   +/-   0.1361170    (guessed as 0.776348 (0.139898))
  ss   =    0.0037770   +/-    0.0015530    (guessed as 0.003589 (0.001617))
  e0   =    0.5608430   +/-    1.8018380    (guessed as 0.642687 (1.861307))
  alpha  =  -0.0061290   +/-   0.0049080    (guessed as -0.005966 (0.005078))
  ss2   =   0.0029050   +/-    0.0009970    (guessed as 0.002686 (0.001078))
  ss3  =    0.0075410   +/-   0.0094220    (guessed as 0.005992 (0.008858))
  ss4  =   -0.0110250   +/-   0.0035850    (guessed as -0.011776 (0.004653))
  ss5  =   -0.0042000   +/-   0.0078070    (guessed as -0.007610 (0.005250))
  alpha2 =  0.0038110   +/-   0.0030450    (guessed as 0.003762 (0.003187))
  alpha3  = -0.0037820   +/-  0.0145580    (guessed as 0.001200 (0.015976))
  alpha4  =  -0.0212550   +/-   0.0107080    (guessed as -0.011852 (0.014417))
  alpha5  =   0.1151980   +/-   0.0236640    (guessed as 0.113430 (0.014973))
  ss6  =   0.0028560   +/-     0.0166050    (guessed as -0.007250 (0.003624))
  alpha6  =  0.0193530   +/-    0.0299640    (guessed as 0.001791 (0.008195))

Def parameters:
  delr_1          =    -0.0279670
  delr_2          =     0.0173920
  delr_3          =    -0.0172570
  delr_4          =    -0.0969910
  delr_5          =     0.5256830
  delr_6          =     0.0883130


Correlations between variables:
         amp and ss         -->  0.8382
          e0 and alpha      -->  0.8048
         amp and ss2        -->  0.7964
          e0 and alpha2     -->  0.7533
         ss3 and alpha5     -->  0.7397
         ss5 and alpha4     --> -0.6999
          ss and ss2        -->  0.6591
       alpha and alpha2     -->  0.6159
      alpha5 and ss6        -->  0.6116
         ss5 and alpha3     --> -0.5790
         ss5 and alpha6     --> -0.5023
         ss3 and ss6        -->  0.4804
      alpha4 and alpha5     --> -0.4375
          e0 and alpha3     -->  0.4083
         ss4 and ss5        --> -0.4047
         ss3 and alpha4     --> -0.3972
      alpha5 and alpha6     -->  0.3827
      alpha3 and alpha6     -->  0.3498
         ss3 and ss5        --> -0.3278
         amp and ss3        -->  0.3209
         ss4 and ss6        -->  0.3181
       alpha and alpha3     -->  0.3100
      alpha2 and alpha3     -->  0.3045
         ss4 and alpha3     -->  0.2948
         amp and ss5        -->  0.2820
         ss2 and alpha6     -->  0.2745
          ss and ss3        -->  0.2627
         ss2 and ss3        -->  0.2626
         amp and alpha6     -->  0.2589
      alpha2 and alpha5     -->  0.2581
All other correlations are below 0.25