Abstract
We study fluctuations in liquid H2O and aqueous solutions of tert-butanol and 2-butoxyethanol. We calculate the fluctuation density and the normalized fluctuation. The former shows the amplitude (or the intensity) of fluctuation, and the latter are indicative of the amplitude plus the wavelength (the extensity) of fluctuation. Three kinds of fluctuations are evaluated, the mean square volume fluctuation, the mean square entropy fluctuation, and the cross fluctuation between volume and entropy. They are calculated using respectively compressibility, heat capacity and thermal expansivity. Using these data, we discuss the peculiarity of liquid H2O, and the details of the mixing schemes in aqueous tert-butanol and 2-butoxyethanol.
