Best fit giving wrong parameter values


I’ve been trying to find the fit for my data using NonLinearModelFit

impedance[R_, L_, C1_, C2_, f_] :=    14.03 + ((R + 2 Pi I f L - I/(2 Pi f C1)) 1/(I 2 Pi f C2))/(    R + I 2 Pi f L + 1/(I 2 Pi f C1) + 1/(I 2 Pi f C2)); absimp[R_, L_, C1_, C2_, f_] =   Simplify[ComplexExpand[Abs[impedance[R, L, C1, C2, f]]]]; NonlinearModelFit[vacamp, (14.03*400)/   absimp[R, L, C1, C2, \[Omega]], {{R, 200}, {L, 10^6}, {C1,     2*10^-12}, {C2, 2*10^-9}}, \[Omega]] 

But this gives me the wrong fit. The data that I have looks approximately like a Gaussian in the range \Omega=32740 to 32800. I tried different starting points but no luck. Would appreciate some help. TIA!