A mass-spectrometric study of Penning ionization of C60 with metastable rare-gas atoms (Rg=He, Ne, Ar, Kr and Xe) shows that the sole channel is C60+ formation. The ionization cross-sections, at an average collision energy of 0.05 eV, strongly decrease from helium to xenon. The interaction potentials for C60 – Rg*, C60+ – Rg, C60 – Rg and C60 – Rg+, and matrix elements for the coupling of the C60–Rg* and C60–Rg+ interactions at the crossing point, have been estimated using recently proposed correlation formulas. The trend of the ionization cross-sections can be explained by the low-energy collisions between Rg* and C60, characterized by the formation of an ion-pair C60–Rg+ intermediate with a decreasing probability on going from lighter to heavier rare gases.
Penning Ionization of C60 Molecules
BRUNETTI, Brunetto Giovanni;CANDORI, Pietro;FALCINELLI, Stefano;VECCHIOCATTIVI, Franco;
1998
Abstract
A mass-spectrometric study of Penning ionization of C60 with metastable rare-gas atoms (Rg=He, Ne, Ar, Kr and Xe) shows that the sole channel is C60+ formation. The ionization cross-sections, at an average collision energy of 0.05 eV, strongly decrease from helium to xenon. The interaction potentials for C60 – Rg*, C60+ – Rg, C60 – Rg and C60 – Rg+, and matrix elements for the coupling of the C60–Rg* and C60–Rg+ interactions at the crossing point, have been estimated using recently proposed correlation formulas. The trend of the ionization cross-sections can be explained by the low-energy collisions between Rg* and C60, characterized by the formation of an ion-pair C60–Rg+ intermediate with a decreasing probability on going from lighter to heavier rare gases.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
