[Ifeffit] path contribution to fit in low R-space position, but the fit bond length is much longer than that

[ZHAN Fei]

Dear all,

  I fit a Zn cluster which RDF has a peak little lower than Zn-S peak,and has a shoulder near Zn-O.This accords with my expection the cluster may have both Zn-S Zn-O bond.But after fit the Zn-O bond length is much larger than reff while it path

contribution after fit did in low R.What's wrong with my fit?is it the big  delro & delrs =0.7882?

sincerely,

zhanfei

this is the fit log,and puc of fit and path contribution is attached

Independent points          : 8.0087891
Number of variables         : 5
Chi-square                  : 2276.2312227
Reduced chi-square          : 756.5273522
R-factor                    : 0.0023036
Measurement uncertainty (k) : 0.0002947
Measurement uncertainty (R) : 0.0004735
Number of data sets         : 1


Happiness = 100.00/100             color = #D8E796
***** Note: happiness is a semantic parameter and should *****
*****    NEVER be reported in a publication -- NEVER!    *****

guess parameters:
  enot               =   8.99859575    # +/-   1.30831421     [0]
  ssS                =   0.01038392    # +/-   0.00062570     [0.00300]
  delrS              =   0.01271583    # +/-   0.00971686     [0]
  ssO                =   0.02806760    # +/-   0.00277795     [0.00300]
  delrO              =   0.33252269    # +/-   0.01446304     [0]

set parameters:
  amp                =   0.85000000
  OC                 =   0.01068708

Correlations between variables:
               delrs & enot               -->  0.9345
               delro & enot               -->  0.8636
               delro & delrs              -->  0.7882
                 sso & enot               --> -0.7422
               delro & sso                --> -0.6014
                 sso & delrs              --> -0.5887
                 sss & enot               -->  0.4980
               delrs & sss                -->  0.4803
                 sso & sss                --> -0.4737
All other correlations below 0.4

===== Data set >> CdSe-ZnS(Fe)-Zn << ====================================

: Athena project       = C:\04-6-29wulizhu\Zn\athena.prj, 3
: name                 = CdSe-ZnS(Fe)-Zn
: k-range              = 3.000 - 10
: dk                   = 1
: k-window             = hanning
: k-weight             = 1,2,3
: R-range              = 1.15 - 3
: dR                   = 0.0
: R-window             = hanning
: fitting space        = r
: background function  = no
: phase correction     =
: R-factor by k-weight = 1 -> 0.01310,  2 -> 0.01474,  3 -> 0.02004

  name        N       S02     sigma^2   e0     delr     Reff     R
=========================================================================
 O1.1      6.360   0.850   0.02807   8.999  0.33252  1.97800  2.31052
 S7.1      3.600   0.850   0.01038   8.999  0.01272  2.34200  2.35472

  name        ei       third     fourth
=========================================
 O1.1     0.00000   0.01069   0.00000
 S7.1     0.00000   0.00000   0.00000

 
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