It seems that chaging the paramet C_TIC from 0 to 2.78 doesn't affect the outpur much. I changed your function slightly so that its vectorised. This makes it easier to plot
Now let's create two versions of this, one with a C_TIC of 0 and one with a C_TIC of 2.78 which represent the extremes of your cc list
func1 = @(x)funH (x,[0 100 303.15]);
func2 = @(x)funH (x,[2,78 100 303.15]);
we can now plot these. Here's func1
x = linspace(-110,-90,50);
and next we we have func2
These look identical to my eyes! Made me wonder if there was any difference at all. Let's plot the difference and see
So they are different but look at the Y axis of the difference plot. These differences are of the order of 10^-10 when the absolute values across the same x-range are of the order of go from -10 to 10.
When you look at your output array, H, which contains all the results of the fsolve command it does indeed look like they are all the same
-100.0000 -100.0000 -100.0000 -100.0000 -100.0000
but if you plot it you'll see that they are different
In short, your code works fine but maybe you might want to rescale your function somehow?