An investigation of evaporation of lithium

The Knudsen effusion method with mass-spectrometric analysis of evaporation products is used to determine the composition and pressure of saturated va por over liquid lithium in the temperature range from 627 to 893 K. The Li( l) = Li(g), 2Li(l) = Li-2(g), and Li-2(g) = 2Li(g) reactions are investigat ed. The measured values of partial pressure for Li and Li-2 are used to cal culate the values of enthalpy for these reactions at 0 K 0 0 by the second, Delta H-r(0)0 (II), and third, Delta H-r(0)0 (III), laws of thermodynamics : Delta H-r(0)0 (II) = 157.9 +/- 0.5, 214.2 +/- 0.6 and 101.4 +/- 1.1 kJ/mo l, and Delta H-r(0)0 (III) = 157.5 +/- 0.3, 213.9 +/- 0.3, and 101.4 +/- 1. 1 kJ/mol, respectively.