Description:Peak shape description for HRPD see isis tf14ls manuals for some description

Why: closer to fundamental parameters description for hrpd and better over large q range than other descriptions

Contributed by: Bill David

macro wifd_pkshape(two_theta,two_thetav,aprm,aprmv,tauf_2,tauf_2v,tauf_1,tauf_1v,tauf_0,tauf_0v,taus_0,taus_0v,taus_1,taus_1v,t_eff,t_effv,hhh,hhhv,hhh_0,hhh_0v) {
	local  !two_theta two_thetav
	local  !lam = 2 D_spacing Sin(0.00872664626 two_theta)  ;
	prm aprm    aprmv min 1.5 max 2.5  
	prm tauf_2  tauf_2v min 0.01
	prm tauf_1  tauf_1v min 0.01 
	prm tauf_0  tauf_0v min 0.001             
	user_defined_convolution = X^aprm Exp(-X / (tauf_0 + tauf_1 lam + tauf_2 lam^2)); min 0 max = 20 aprm tauf_1 lam;
 
	prm taus_0  taus_0v min 0.001 
	prm taus_1  taus_1v min 0.001 
	prm t_eff  t_effv min 90.0
	local storage = Exp( -950 /(t_eff lam lam)) ;			
        push_peak 
                prm hhh  hhhv min .001 
                prm hhh_0  hhh_0v min 0.001
                hat = hhh_0 + hhh D_spacing; 
                scale_top_peak = (1-storage); 
        bring_2nd_peak_to_top 
		  			 hat = hhh_0 + hhh D_spacing;
                scale_top_peak = storage;   
                exp_conv_const = -Ln(0.001) (taus_0 + lam taus_1); 
        add_pop_1st_2nd_peak 
}

Some caveat emptor values to get you going are:

wifd_pkshape(two_theta, 168.567, aprm, 2.50000`_0.62706, tauf_2, 9.80744`_5.89895, tauf_1, 0.43977`_0.10151, !tauf_0, 0.000, taus_0, 25.27420`_0.20815, taus_1, 2.66797`_0.09213, t_eff, 144.41296`_0.54047, hhh, 3.58595`_5.10736, hhh_0, 11.61348`_1.21068)		  
wifd_pkshape(two_theta, 90.2481, aprm, 2.50000`_0.62706, tauf_2, 9.80744`_5.89895, tauf_1, 0.43977`_0.10151, !tauf_0, 0.000, taus_0, 25.27420`_0.20815, taus_1, 2.66797`_0.09213, t_eff, 144.41296`_0.54047, hhh, 3.58595`_5.10736, hhh_0, 11.61348`_1.21068)		  
wifd_pkshape(two_theta, 29.9309, aprm, 2.50000`_0.62706, tauf_2, 9.80744`_5.89895, tauf_1, 0.43977`_0.10151, !tauf_0, 0.000, taus_0, 25.27420`_0.20815, taus_1, 2.66797`_0.09213, t_eff, 144.41296`_0.54047, hhh, 3.58595`_5.10736, hhh_0, 11.61348`_1.21068)