Deexcitation cross sections of Ne(3P2, 3P1, and 3P) by molecules containing group-IV elements

Deexcitation cross sections of Ne(3P2), Ne(3P1), and Ne(3P0) by CH4, SiH4, GeH4, CF4, and SiF4 have been measured at a mean collisional energy corresponding to room temperature (295 K) and compared systematically with those by other molecules to understand general features of the cross section values dependent on both the electronic states of excited neon atoms and the target molecules. A small difference in the cross section values between metastable atoms, Ne(3P2) and Ne(3P0), and a resonant atom, Ne(3P1), has indicated that Penning ionization by Ne(3P1) is mainly governed by an electron exchange interaction rather than a dipole–dipole interaction. A spatial electron distribution of the outermost orbital of a target molecule is especially of great importance in the determination of the absolute cross section values in the deexcitation of excited neon atoms due to an electron exchange interaction.