Measurement of Monoatomic Vapor Concentrations of Some Elements by Atomic Absorption Spectrophotometry: Cu, Ag, Au, Mn, and Al

Abstract

Measurement of the absorbance of resonance radiation from a hollow cathode lamp has been used to study the concentration of monoatomic metal vapor in equilibrium with its solid phase in an inert argon atmosphere (two Torr) over a pressure range 10−7 – 10−4 Torr for copper, silver, gold, manganese, and aluminum. The results obtained by this technique are compared with the vapor pressure data obtained by other workers using different techniques. The monoatomic vapor pressure data plotted against the reciprocal of temperature give a straight line, and the mean enthalpies of vaporization have been calculated from the slope of this line. The enthalpies are in agreement with the values obtained by earlier investigators using different techniques for copper, silver, gold, and manganese, but tend to be lower in the case of aluminum. The absolute vapor pressures calculated by this approach are higher for aluminum in the range of investigations.