Mercury Vapor Pressure at Low Temperatures

Abstract

Mercury vapor pressure, 20° to -80°C.—A modified Buckley ionization gage is described with a range from ${10}^{-2\mathrm{}}$ to 4×${10}^{-9\mathrm{}}$ mm. This was used to measure the vapor pressure of mercury. Correction for thermal effusion was made, ranging from 25 percent at -80°C to zero at 0°C. The gage was calibrated at 0°C from Knudsen's value. The results correspond to the equations ${log}_{10}P\left(\mathrm{liquid}\right)=8.86-3.44\left(\frac{{10}^3}{T}\right)$; ${log}_{10}p\left(\mathrm{solid}\right)=9.35-3.55\left(\frac{{10}^3}{T}\right)$.