A Compact Form for the Analytic Description of Temperature Dependence of Saturation Vapor Pressure over Plane Surfaces of Water and Ice

N. P. Romanov

A possibility is studied of extending the range of action of the simple three-parameter formula (ITS-90 scale) proposed in the previous work of the author [2] for the dependence of saturation vapor pressure E on temperature T within the range of 250 to 490 K. The results demonstrated that the dependence ln[E(T)/E(Tbas)] = (T – Tbas)[A – B(T – Tbas) + C(T – Tbas)2]/T with four sets of coefficients A, B, and C obtained using one base temperature Tbas equal to the temperature of triple point of water Tt = 273.16 K and two additional base values Tbas2 = 473.16 K and Tbas3 = 623.16 K makes it possible to approximate rather accurately the initial experimental and computed data in the temperature range from the point of homogeneous freezing of 235 K to the critical temperature of 647 K for liquid water and from 193 K to Tt for ice. A procedure used for obtaining the inverse function T(E) by solving the third-degree algebraic equation is validated. A hypothesis is proposed for the physical substantiation of additional base points in the form of “a noticeable appearance of dimers at the point Tbas2 and their 100% concentration at the temperature Tbas3.”

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