Function Description
********************

	Name: Z_DISP 
	Function: jFit dispersion 
	Parameters: Vo(1) T1(1) Vo(2) T1(2) Mo F 

Notes
*****

Not sure if this one is working. I will have to consult my old notes
on jfit...let me know if you care.

C-code for the function
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	b = 4.0 * PI * PI;
	c = 2.0 * PI * a[1] * a[1] * (x-a[0]);
	lz1 = c / (1 + b * (x-a[0])*(x-a[0]) * (a[1]*a[1]));
	c = 2.0 * PI * a[3] * a[3] * (x-a[2]);
	lz2 = c / (1 + b * (x-a[2])*(x-a[2]) * (a[3]*a[3]));
	answer = (a[4] * (lz1 - a[5]*lz2));