I have calculated the real and imaginary value of susceptibility from UV-Vis absorbance of R6G dye using K-K relation in MATLAB. But when I convert these values to refractive index the imaginary part value is coming of the order of (10^-15) within 300-900 nm wavelength region. Is it correct? The conversions I used

Real mu = sqrt(1 + (susceptibility{real}/epsilon0))

Imag mu = sqrt((susceptibility{Imag}/epsilon0). The article which I followed for the conversion is attached. Thank you in advance.