Difference between revisions of "Temp"

From Ug11bm
Jump to navigationJump to search
Line 3: Line 3:
A quick reference for the various profile type 3 and 4 terms is given below.  Users are ''strongly'' encouraged to read this section of the manual at least once before (or after) blindly using this guide.
A quick reference for the various profile type 3 and 4 terms is given below.  Users are ''strongly'' encouraged to read this section of the manual at least once before (or after) blindly using this guide.


These peak profile function are a [http://en.wikipedia.org/wiki/Voigt_profile pseudo-Voigt] type, combining Gaussian and Lorentzian components.
These peak profile functions are a [http://en.wikipedia.org/wiki/Voigt_profile pseudo-Voigt] type, combining Gaussian (G) and Lorentzian (L) components.
 
The general Gaussian shape is described by the Cagliotti function
 
Gaussian &asymp


   
   
cosθ
cosθ


Line 53: Line 56:
| '''S/L''' = Finger-Cox Axial Divergence S term
| '''S/L''' = Finger-Cox Axial Divergence S term
| '''H/L''' = Finger-Cox Axial Divergence H term
| '''H/L''' = Finger-Cox Axial Divergence H term
| '''eta''' = mixing factor, from Gaussian (0) to Lorentzian (1)
| '''eta''' = mixing factor, from pure Gaussian (0) to pure Lorentzian (1)
|-
|-
| '''SXXX''' = Stephens anisotropic microstrain broadening
| '''SXXX''' = Stephens anisotropic microstrain broadening

Revision as of 04:40, 2 May 2012

GSAS offers 5 different Constant Wavelength (CW) X-ray profile functions. They are described in detail within the GSAS technical manual (see page 156). 11-BM users are encouraged to use either profile type 3 or type 4.

A quick reference for the various profile type 3 and 4 terms is given below. Users are strongly encouraged to read this section of the manual at least once before (or after) blindly using this guide.

These peak profile functions are a pseudo-Voigt type, combining Gaussian (G) and Lorentzian (L) components.

The general Gaussian shape is described by the Cagliotti function

Gaussian &asymp 


cosθ


Constant Wavelength X-ray GSAS Profile Type 3

GU = Gaussian U term GV = Gaussian V term GW = Gaussian W term
GP = Gaussian crystallite size broadening LX = Lorentzian crystallite size broadening LY = Lorentzian strain broadening
S/L = Finger-Cox Axial Divergence S term H/L = Finger-Cox Axial Divergence H term trns = sample transparency
shft = sample displacement stec = anisotropic strain ptec = anisotropic crystallite size
sfec = sublattice anisotropic broadening (stacking faults) LXX = Lorentzian microstrain anisotropy LYY = Lorentzian microstrain anisotropy


Constant Wavelength X-ray GSAS Profile Type 4

GU = Gaussian U term GV = Gaussian V term GW = Gaussian W term
GP = Gaussian crystallite size broadening LX = Lorentzian crystallite size broadening ptec = anisotropic crystallite size
trns = sample transparency shft = sample displacement sfec = sublattice anisotropic broadening (stacking faults)
S/L = Finger-Cox Axial Divergence S term H/L = Finger-Cox Axial Divergence H term eta = mixing factor, from pure Gaussian (0) to pure Lorentzian (1)
SXXX = Stephens anisotropic microstrain broadening SYYY = Stephens anisotropic microstrain broadening SZZZ = Stephens anisotropic microstrain broadening