THE TRIPLE-IONIZATION ENERGY OF KRYPTON MEASURED BY TRIPLE-CHARGE-TRANSFER SPECTROMETRY

In a recent publication, it has been shown that fast-moving O2+ and Cl 2+ ions can undergo triple-electron-capture reactions in single collis ions with xenon atoms. Peaks in the negative-ion spectra were identifi ed with transitions to known electronic states of Xe3+, thus allowing the negative-ion translational-energy scale to be converted into a tri ple-ionization-energy scale. The technique, given the name triple-char ge-transfer spectrometry, thus has the potential of being used in the determination of triple-ionization energies of atoms and molecules. In order to investigate this possibility, it has been used in this study to determine the triple-ionization energy of krypton, having first ca librated the translational-energy scale using triple-electron-capture reactions with xenon. The result obtained is 75.8+/-0.9 eV; this is in agreement with the known value of 75.5 eV, and thus provides the ince ntive to apply the technique to molecules for which the triple-ionizat ion energies are unknown.