Energy-dependent collision cross section as estimated from temperature-dependent rate coefficient: disalignment of excited neon atoms by neon collisions

Laser-induced-fluorescence spectroscopy has been applied to a neon discharge plasma. A disalignment rate coefficient for 2p 2 (Paschen notation; 2p 5 3p configuration) atoms for neon atom collisions was determined at several atom temperatures (77-640 K). From the temperature dependence of the rate coefficient we estimate the cross section which explicitly depends on collision energy. The cross section has a positive energy dependence, which suggests that the Omega = 0 and 1 molecular potential curves correlating to the 2p 2 state of neon are repulsive by about 100 cm -1 where these curves split by 10-20 cm -1 .