Temperature dependence of the acentric factor of normal hydrogen, orthohydrogen and parahydrogen

Temperature-dependence correlations of vapor pressure and acentric factor for normalhydrogen( n-H 2 ), orthohydrogen( o-H 2 ) and parahydrogen( p-H 2 ), have been formulated. The obtained correlations are statistically excellent. The characteristic parameters such as the Pitzer’s acentric factor, Riedel’s parameter, Filippov’s parameter have been determined for n-H 2 , o-H 2 and p-H 2 . And, the curvatures of vapor pressure curve for n-H 2 , o-H 2 and p-H 2 have been determined in a wide range of temperature. It is found that the curvatures of vapor pressure curve for n-H 2 , o-H 2 and p-H 2 have a maximum at about 17.11K, 17.12K and 17.00K, respectively.