Home > Scripts > Models > Specialized > sqw_cubic_monoatomic.m

iFit/sqw_cubic_monoatomic

PURPOSE ^

model = sqw_cubic_monoatomic(p, h,k,l,w, {signal}) : cubic monoatomic dispersion(HKL) with DHO(energy)

SYNOPSIS ^

function signal=sqw_cubic_monoatomic(varargin)

DESCRIPTION ^

 model = sqw_cubic_monoatomic(p, h,k,l,w, {signal}) : cubic monoatomic dispersion(HKL) with DHO(energy)

   iFunc/sqw_cubic_monoatomic: a 4D S(q,w) with a HKL dispersion, and a DHO line
      shape, for a simple monoatomic system on a cubic lattice. Only the 3 
      acoustic modes are computed.

 WARNING:
      Single intensity and line width parameters are used here.
      The HKL position is relative to the closest Bragg peak. 

 Example:
 s=sqw_cubic_monoatomic([2 3]); qh=linspace(0,.5,50);qk=qh; ql=qh; w=linspace(0.01,10,51);
 f=iData(s,[],qh,qk,ql,w); scatter3(log(f(:,:,1,:)),'filled');

 References: https://en.wikipedia.org/wiki/Phonon
  E. Meisterhofer <http://lampx.tugraz.at/~hadley/ss1/phonons/scdos/sc.pdf> 2013
  Kittel, Solid State Physics, Wiley, New York, 7th ed. (1996), pp 99-103.

 input:  p: sqw_cubic_monoatomic model parameters (double)
           p(1)=C_ratio C1/C2 force constant ratio first/second neighbours.
           p(2)=E0      sqrt(C1/m) energy [meV]
           p(3)=Gamma   dispersion DHO half-width in energy [meV]
           p(4)=Temperature of the material [K]
           p(5)=Amplitude
           p(6)=Background (constant)
         qh: axis along QH in rlu (row,double)
         qk: axis along QK in rlu (column,double)
         ql: axis along QL in rlu (page,double)
         w:  axis along energy in meV (double)
    signal: when values are given, a guess of the parameters is performed (double)
 output: signal: model value

 Version: Mar. 22, 2017
 See also iData, iFunc/fits, iFunc/plot, gauss, sqw_phonons, sqw_sine3d, sqw_vaks
   <a href="matlab:doc(iFunc,'Models')">iFunc:Models</a>
 (c) E.Farhi, ILL. License: EUPL.

CROSS-REFERENCE INFORMATION ^

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