Hi Mailing list, I'm back at fitting commercial Molybdenum Disulfide to a Hexagonal p 63/m m c space group. Although my present fit is reasonable, thanks to the mailing list in August, I was hoping someone might have more suggestions to optimize it. Also, in order to better my fit, I still have seperate e0's, one for the first path, one for the remaining 2 paths. I haven't gotten a satisfactory physical explanation for this and I thought someone might have a good one. Also, the data on the same sample from two different beamlines seems to be somewhat different, namely the Reduced chi-square is very different (75.6 in one, 636.4 in the other). In both cases I use the first 3 single scattering paths. I may have included too much info, but better too much than too little. Thank You, Dan Carter Here are my parameters in both cases, values differ somewhat: Set: Amp = 0.7 guess: eO ~ 1.57 (1.52) (used for first path) guess: eO_1 ~ -4.77 (2.43) (used for remaining 2 paths) guess: ss ~ 0.0027 (0.000427) guess: alpha ~ -0.004 (0.003255) (positive for second fit) delr_1: alpha*reff First Fit: Project title : Fitting merge 10_15_04.chi Comment : Prepared by : Contact : Started : 11:49:36 on 22 October, 2004 This fit at : 11:10:57 on 28 October, 2004 Environment : Artemis 0.7.010 using Windows 2000, perl 5.006001, Tk 800.024, and Ifeffit 1.2.6 ============================================================ Independent points = 14.312500000 Number of variables = 4.000000000 Chi-square = 779.303886008 Reduced Chi-square = 75.568861674 R-factor = 0.041210572 Measurement uncertainty (k) = 0.000827712 Measurement uncertainty (R) = 0.022111003 Number of data sets = 1.000000000 Guess parameters +/- uncertainties (initial guess): e0_1 = -4.7737110 +/- 2.4268840 (guessed as -4.773687 (2.426889)) ss = 0.0027360 +/- 0.0004270 (guessed as 0.002736 (0.000427)) e0 = 1.5684690 +/- 1.5209160 (guessed as 1.568507 (1.520918)) alpha = -0.0040060 +/- 0.0032550 (guessed as -0.004006 (0.003255)) Def parameters: delr_1 = -0.0158980 Set parameters: amp = 0.7 Correlations between variables: e0_1 and alpha --> 0.8622 e0 and alpha --> 0.7870 e0_1 and e0 --> 0.7064 All other correlations are below 0.25 Project title : Fitting merge 10_15_04.chi Comment : Prepared by : Contact : Started : 11:49:36 on 22 October, 2004 This fit at : 11:10:57 on 28 October, 2004 Environment : Artemis 0.7.010 using Windows 2000, perl 5.006001, Tk 800.024, and Ifeffit 1.2.6 ============================================================ Independent points = 14.312500000 Number of variables = 4.000000000 Chi-square = 779.303886008 Reduced Chi-square = 75.568861674 R-factor = 0.041210572 Measurement uncertainty (k) = 0.000827712 Measurement uncertainty (R) = 0.022111003 Number of data sets = 1.000000000 Guess parameters +/- uncertainties (initial guess): e0_1 = -4.7737110 +/- 2.4268840 (guessed as -4.773687 (2.426889)) ss = 0.0027360 +/- 0.0004270 (guessed as 0.002736 (0.000427)) e0 = 1.5684690 +/- 1.5209160 (guessed as 1.568507 (1.520918)) alpha = -0.0040060 +/- 0.0032550 (guessed as -0.004006 (0.003255)) Def parameters: delr_1 = -0.0158980 Set parameters: amp = 0.7 Correlations between variables: e0_1 and alpha --> 0.8622 e0 and alpha --> 0.7870 e0_1 and e0 --> 0.7064 All other correlations are below 0.25 ===== Data set >>merge 6_17_04.chi<< ======================================== file: C:\Ifeffit\horae\stash\artemis.project.3\chi_data\merge 6_17_04.chi title lines: Athena data file -- Athena version 0.8.032 Saving merge 6_17_04 (group=merge) as chi(k) . Element=Mo Edge=K Background parameters . E0=20007.492 Eshift=0.000 Rbkg=1.000 . Standard=None . Kweight=2.0 Edge step=0.749 . Fixed step=no Flatten=yes . Pre-edge range: [ -150.000 : -75.000 ] . Normalization range: [ 150.000 : 895.199 ] . Spline range: [ 0.952 : 995.207 ] Clamps: None/Strong Foreward FT parameters . Kweight=2 Window=kaiser-bessel Phase correction=no . k-range: [ 2.000 : 16.100 ] dk=0.00 Backward FT parameters . R-range: [ 1.000 : 3.000 ] . dR=0.00 Window=kaiser-bessel Plotting parameters . Multiplier=1 Y-offset=0.000 . Merge in k space of: ** C:/USERS/Dan2/raw data MoS2 6_17_04/MoS2.101 (mos2_101) ** C:/USERS/Dan2/raw data MoS2 6_17_04/MoS2.102 (mos2_102) ** C:/USERS/Dan2/raw data MoS2 6_17_04/MoS2.103 (mos2_103) ** C:/USERS/Dan2/raw data MoS2 6_17_04/MoS2.104 (mos2_104) k-range = 2.000 - 13.500 dk = 2.000 k-window = kaiser-bessel k-weight = 2 R-range = 1.000 - 3.000 dR = 0.100 R-window = kaiser-bessel fitting space = R background function = none phase correction = none R-factor for this data set = 0.74613 Second Fit: Project title : Fitting merge 10_15_04.chi Comment : Prepared by : Contact : Started : 11:49:36 on 22 October, 2004 This fit at : 11:23:36 on 28 October, 2004 Environment : Artemis 0.7.010 using Windows 2000, perl 5.006001, Tk 800.024, and Ifeffit 1.2.6 ============================================================ Independent points = 14.312500000 Number of variables = 4.000000000 Chi-square = 6562.747150466 Reduced Chi-square = 636.387602469 R-factor = 0.032979787 Measurement uncertainty (k) = 0.000181935 Measurement uncertainty (R) = 0.004860095 Number of data sets = 1.000000000 Guess parameters +/- uncertainties (initial guess): e0_1 = -4.0720090 +/- 1.9194040 (guessed as -4.773711 (2.426884)) ss = 0.0046360 +/- 0.0004110 (guessed as 0.002736 (0.000427)) e0 = 1.7659580 +/- 1.1543880 (guessed as 1.568469 (1.520916)) alpha = 0.0010900 +/- 0.0028430 (guessed as -0.004006 (0.003255)) Def parameters: delr_1 = 0.0043250 Set parameters: amp = 0.7 Correlations between variables: e0_1 and alpha --> 0.8416 e0 and alpha --> 0.8045 e0_1 and e0 --> 0.7141 All other correlations are below 0.25 ===== Data set >>merge 10_15_04.chi<< ======================================== file: C:\Ifeffit\horae\stash\artemis.project.3\chi_data\merge 10_15_04.chi title lines: Athena data file -- Athena version 0.8.032 Saving merge 6_17_04 (group=merge) as chi(k) . Element=Mo Edge=K Background parameters . E0=20007.492 Eshift=0.000 Rbkg=1.000 . Standard=None . Kweight=2.0 Edge step=0.749 . Fixed step=no Flatten=yes . Pre-edge range: [ -150.000 : -75.000 ] . Normalization range: [ 150.000 : 895.199 ] . Spline range: [ 0.952 : 995.207 ] Clamps: None/Strong Foreward FT parameters . Kweight=2 Window=kaiser-bessel Phase correction=no . k-range: [ 2.000 : 16.100 ] dk=0.00 Backward FT parameters . R-range: [ 1.000 : 3.000 ] . dR=0.00 Window=kaiser-bessel Plotting parameters . Multiplier=1 Y-offset=0.000 . Merge in k space of: ** C:/USERS/Dan2/raw data MoS2 6_17_04/MoS2.101 (mos2_101) ** C:/USERS/Dan2/raw data MoS2 6_17_04/MoS2.102 (mos2_102) ** C:/USERS/Dan2/raw data MoS2 6_17_04/MoS2.103 (mos2_103) ** C:/USERS/Dan2/raw data MoS2 6_17_04/MoS2.104 (mos2_104) k-range = 2.000 - 13.500 dk = 2.000 k-window = kaiser-bessel k-weight = 2 R-range = 1.000 - 3.000 dR = 0.100 R-window = kaiser-bessel fitting space = R background function = none phase correction = none R-factor for this data set = 0.71585 Paths used to fit Both Data Sets, degen, s02 the same. other values different: F1 p 63/m m c: feff0001.dat .. feff = C:\Ifeffit\horae\stash\artemis.project.3\data0.feff2\feff0001.dat id = reff= 2.4135, nlegs= 2, path= Mo<->S label = r = 2.416130 degen = 6.000000 s02 = 0.700000 e0 = 1.765958 dr = 0.002630 ss2 = 0.004636 F1 p 63/m m c: feff0002.dat .. feff = C:\Ifeffit\horae\stash\artemis.project.3\data0.feff2\feff0002.dat id = reff= 3.1500, nlegs= 2, path= Mo<->Mo label = r = 3.153433 degen = 6.000000 s02 = 0.700000 e0 = -4.072009 dr = 0.003433 ss2 = 0.004636 F1 p 63/m m c: feff0003.dat .. feff = C:\Ifeffit\horae\stash\artemis.project.3\data0.feff2\feff0003.dat id = reff= 3.9683, nlegs= 2, path= Mo<->S label = r = 3.972625 degen = 6.000000 s02 = 0.700000 e0 = -4.072009 dr = 0.004325 ss2 = 0.004636