Ionization energies of hypervalent Li ₂ F, Li ₂ Cl and Na ₂ Cl molecules obtained by surface ionization electron impact neutralization mass spectrometry

Abstract

Abstract Ionization energies of hypervalent Li 2 F, Li 2 Cl and Na 2 Cl molecules detected by surface ionization electron impact neutralization mass spectrometry are reported. The ionization energies were 3.78 ± 0.2 eV for Li 2 F, 4.93 ± 0.2 eV for Li 2 Cl, and 4.21 ± 0.2 eV for Na 2 Cl. The ionization energies (IE) agree with theoretical ionization energies calculated by ab initio methods, supporting the theoretical prediction that Li 2 F has a hyperlithiated configuration in which the odd electron delocalizes over the two lithiums and with photoionization measurement. The first ionization energy of Na 2 Cl was experimentally confirmed earlier and for Li 2 Cl as well. We have developed and used this new approach for the problem—in the present work ions were first formed by surface ionization, followed by electron attachment (neutralization). Copyright © 2002 John Wiley & Sons, Ltd.