The effect of temperature on fluctuation functions in pure H2O and n-hexane: Wavelength (extensity) vs. amplitude (intensity)

We introduced earlier the concept of the extensity vs. intensity, or the wavelength vs. amplitude, of fluctuation functions. It is generally accepted, on the other hand, that the temperature increase causes a decrease in the global average of the hydrogen bond probability in pure H2O. A question arises immediately whether the temperature increase primarily affects the extensity or the intensity of fluctuations. We here address this question to liquid H2O and n-hexane. We conclude that it is the extensity of fluctuation functions for H2O that are affected, in comparison with n-hexane. As long as we limit ourselves within the low pressure and temperature region in the p-T variable field where the integrity of liquid H2O is retained. Namely, in this particular p-T region, the hydrogen bonds in liquid H2O are fluctuating vigorously and yet the hydrogen bond network in liquid H2O is bond-percolated. (C) 2018 Elsevier B.V. All rights reserved.