Spectral and Temperature Dependence of Laser Induced Dissociative Attachment in SF₆

Abstract

We consider the influence of resonant laser excitation upon the dissociative reaction between SF₆ molecules and very low energy electrons. Experimentally, the use of valence electrons of atoms in Rydberg states ensures a well-defined energy resolution of the scattering electrons in the crossed beam apparatus. A spectroscopic model of the infrared absorption of CO₂ laser radiation by SF₆ gives a fair determination of the energy levels and vibrational transitions involved in the dissociative process. This reaction between highly excited atoms and a molecule is interpreted as a three step process: attachment of a quasi-free electron, followed by the interaction between the atomic ionic core and the negative molecular ion leading to a partial stabilization and, finally, the competition between the dissociating and the autodetachment channels.