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

	Name: Z_UCD (UC_DIMER)
	Function: f(x) = m + a0**2*ka * exp(h*2M*(x*x-x0*x0)) 
	Parameters: a0 h M X0 Ka2 

Notes
*****

	Old function, I'm not sure who suggested it to me anymore.

C-code for the function
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	c = a[0] * exp(a[1] * a[2] * (x - a[3]));
	d = a[0] * a[0] * a[4] * exp(a[1] * a[2] * 2 * (x - a[3]));
	answer = c + d;