ATOMIZATION ENTHALPIES OF THE MOLECULES CU-3, AG-3, AND AU-3

The gaseous species in equilibrium with Cu(1), Ag(1), and Au(1) were investigated by vaporization studies according to the method of high temperature mass spectrometry with a Knudsen cell. From the observed ion intensity ratios of dimer to monomer and of trimer to monomer the dissociation enthalpies of Cu//2, Ag//2, and Au//2 were redetermined. It is found that the mean temperature of the measurements of 1849 K (Cu), 1500 K (Ag), and 1883 K (Au) the vapor pressures of the trimers are by a factor of 2. 4 multiplied by (times) 10**7 (Cu//3), 2. 9 multiplied by (times) 10**7 (Ag//3), and 1. 7 multiplied by (times) 10**7 (Au//3) smaller than those of the corresponding monomers. This work is pertinent to catalysis.