# [Ifeffit] Spine Clamps and Some Fit Results

dmc at pdx.edu dmc at pdx.edu
Wed Jan 28 14:35:13 CST 2004

```Dear Panel of Feffit Experts,

I have two questions for you, with several parts.
I am looking at Lithium Cobalt Oxide annealed at 200 C.

(1) In Athena what exactly do the varying levels of spine clamps mean?  When do
I need to use them?  I've been ignoring them up to now, but I think that it
might help my resulting fit, which brings me to my second part.

(2) By looking at my results is there any advice you can give me?  Do my
reduced chi-squared, R-factor and correlated variables look good?  I know that
the R-Factor should be below 0.05, but what about red chi-squared (depends on
the material)?
Also, I am concerened that my amp (SO^2) should be closer to 1.  I am
using the einstien model and e01 refers to the farther 3 of my 4 paths.  What
else should I consider?

Thanks, Dan Carter
Hunter College

Results:

Independent points          =      11.225585938
Number of variables         =       5.000000000
Chi-square                  =      66.894398861
Reduced Chi-square          =      10.745076774
R-factor                    =       0.040027549
Measurement uncertainty (k) =       0.002990761
Measurement uncertainty (R) =       0.069932022
Number of data sets         =       1.000000000

Guess parameters +/- uncertainties:
e0              =    -3.9151859   +/-      2.3534572
delr            =    -0.0189516   +/-      0.0134287
ampg            =     0.9492922   +/-      0.0001603
e01             =    -9.3741702   +/-      2.5615506
theta           =   415.2229263   +/-     89.8481275

Restraints:
amp             =     0.7077880

Set parameters:
ampt            =     0.9500000
scale           =  1000.0000000
temp            =   300.0000000

Correlations between variables:
ampg and theta      --> -0.9015
delr and e01        -->  0.8551
e0 and delr       -->  0.7809
e0 and e01        -->  0.6858
All other correlations are below 0.25

```