How are the vapor pressure and enthalpy of vaporization in materials generally measured?

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How are the vapor pressure and enthalpy of vaporization in materials generally measured? For many materials, including pesticide and drug samples, it is urgently necessary to have information on their vapor pressure in order to prevent the accumulation of toxic compounds in the environment. The vapor pressure is directly related to the initial Gibbs free energy of solid/liquid materials. The DVS Vacuum instrument uses a Knudsen cell to measure the vapor pressure of liquids or solids. There is a small hole in Knudsen cell, and the mass loss rate is related to the vapor pressure P in the condensed state; the Knudsen equation can be used to calculate this vapor pressure. By testing a series of vapor pressures at different temperatures, the enthalpy of vaporization ΔH, or the sublimation heat, can be calculated using the Clausius-Clapeyron equation.