topas wiki

'GSAS background function 6 - GSAS manual page 130
'to model rise at low Q (air scatter) and high Q (thermal diffuse scattering)
'NOTE Topas will not currently plot this function on the difference plot
'P. Whitfield
macro Bkg_GSAS_f6(bk1, b1v, bk2, b2v, bk3, b3v, bk4, b4v, bk5, b5v, bk6, b6v, bk7, b7v, bk8, b8v, bk9, b9v, bk10, b10v, bk11, b11v, bk12, b12v, bk13, b13v, bk14, b14v, bk15, b15v)
{
   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 bk9 b9v
   prm bk10 b10v
   prm bk11 b11v
   prm bk12 b12v
   prm bk13 b13v	
   prm bk14 b14v
   prm bk15 b15v		
   prm Q = 4 Pi Sin(X Deg_on_2) / Lam;
 
   fit_obj = bk1 + (bk2 Q^2 + bk3/Q^2) +
	(bk4 Q^4/2 + 2 bk5/Q^4) +
	(bk6 Q^6/6 + 6 bk7/Q^6) +
	(bk8 Q^8/24 + 24 bk9/Q^8)+
	(bk10 Q^10/120 + 120 bk11/Q^10) +
	(bk12 Q^12/720 + 720 bk13/Q^12) +
	(bk14 Q^14/5040 + 5040 bk15/Q^14)	
	;
}