topas wiki

'GSAS background function 5 - GSAS manual page 130
'to model rise at low Q (air scatter)
'NOTE Topas currently will not plot the function on the difference plot
'P. Whitfield
macro Bkg_GSAS_f5(bk1, b1v, bk2, b2v, bk3, b3v, bk4, b4v, bk5, b5v, bk6, b6v, bk7, b7v, bk8, b8v)
{
   prm bk1 b1v  
   prm bk2 b2v
   prm bk3 b3v  
   prm bk4 b4v
   prm bk5 b5v  
   prm bk6 b6v
   prm bk7 b7v  
   prm bk8 b8v	
   prm Q = 4 Pi Sin(X Deg_on_2) / Lam;
 
   fit_obj = bk1 + bk2 /Q^2 + 2 bk3 /Q^4 + 6 bk4 /Q^6 + 24 bk5/Q^8 + 120 bk6/Q^10 + 720 bk7/Q^12 + 5040 bk8/Q^14;
}