A kinetic study of electronically metastable nitrogen atoms, N(2 2Dj), is presented. Metastable nitrogen atoms are produced by microwave discharge of N2 diluted in He in a fast flow system. The concentration of N(2D5/2i3/2) is monitored by using electron spin resonance spectroscopy. Deactivation rate constants are reported for N(í)j) with the gases N20,

were determined between 300 and 800 K from relative rate measurements by using SF 6 as a reference compound. A flowing afterglow-electron cyclotron resonance technique was employed. Mass spectral analysis of product negative ions confirmed a dissociative attachment mechanism. Semiempirical quantum mechanical calculations of the geometry change associated with negative ion formation were carried out.

The absolute rate constants for the reactions of atomic hydrogen with CF3, CF2, and CF radicals have been measured in a gas flow system with photoionization mass spectrometry detection. CF3, CF2, and CF were produced by dissociation of CF3Br, CF2HC1, and CH2FC1, respectively, in a radio frequency discharge. H atoms were produced by dissociation of the elemental gas in a microwave discharge. The pressure was 1.7 Torr. The rate constants at 293 K in units of cm3 molecule"1 s"1 are (9.1 ± 1.5) X 10"11 for CF3 + H, (3.9 ± 0.7) X 10"11 for CF2 + H, and (1.9 ± 0.3) X 10"11 for CF + H. Hydrogen fluoride was detected as the principal stable product in all three reactions. The mechanism of fluorine atom abstraction is discussed.

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