Binding energies of LiH2and LiH2+and the ionization potential of LiH2

摘要

The existence of the stable molecule LiH2was proved experimentally for the first time by mass spectrometric measurements over dilute solutions of hydrogen in liquid lithium. From the measurements of the gaseous equilibria Li(g)+LiH2(g) =2 LiH(g), and LiH2(g)+Li2(g) =LiH(g)+Li2H(g), an atomization energy Ddeg;0(LiH2) =127.0plusmn;7 kcal/mole was obtained. The ionization potential of LiH2(g) was determined as I.P. (LiH2) =6.14plusmn;0.2 eV, from which the binding energy of the ion LiH+2, Ddeg;0(LiH+2) =109.0plusmn;8 kcal/mole was deduced. The heat of formation was determined as Dgr;Hdeg;0(LiH2) =14.75plusmn;7.0 kcal/mole. The results from this study were compared with those predicted using diatomichyphen;inhyphen;molecules and valence only electronic structure theories.