Vibrational energy relaxation (<i>V</i>–<i>T</i>) of highly compressed n-H2 gas in the 77–293 K temperature range

Abstract

Experimental measurements of the vibrational relaxation time of normal hydrogen have been carried out in the dense gas phase over a wide range of pressures (0–300 MPa) for three different temperatures (77, 196, and 293 K). We analyze our results in terms of different high density fluid relaxation theories which generally consider only binary collision processes. These theories were used with success by several authors to explain the variation of their experimental results on liquid hydrogen and oxygen; unfortunately, they disagree with our measurements. Nevertheless, an experimental linear relationship between the vibrational relaxation time and the self-diffusion coefficient was found as suggested by Zwanzig.