Difference between revisions of "Temp"
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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 | 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 |
