| Abstrakt: |
Dissociative electron attachment (DEA) to CH[sub 3]NO[sub 2] in the gas phase was studied in the electron energy range from zero up to 10 eV with an energy resolution of 140 meV. For the most intense negative fragments NO[sup -, sub 2], O[sup -], OH[sup -], CN[sup -], CNO[sup -] estimates for the absolute partial cross sections were obtained for the first time [σ(NO[sub 2])≈10[sup -21]m² at 0.62 eV, σ(O[sup -])≈ 10[sup -23]m² at 5.4 eV, σ(OH[sup -])≈10[sup -24]m² at 4 eV, σ(CN[sup -])≈10[sup -24]m² at 1.7 eV, and σ(CNO[sup -]) ≈ 10[sup -25]m² at 4 eV]. In the case of OH[sup -], CN[sup -], and CNO[sup -], ion formation at very low electron energies (≈0 eV) has been observed in contrast to previous studies. The formation of OH[sup -] and CNO[sup -] at these low electron energies is explained in terms of DEA to vibrationally excited molecules. Analyzing measured partial cross sections, the standard enthalpy of formation of the CH[sub 3]NO (nitroso-methane) and the CNO radical has been estimated, as Δ[sub f]H[sup º, sub g],(CH[sub 3]NO)=129±30 kJ/mol and Δ[sub f]/H[sup º,, sub g](CNO)=323 ± 30 kJ/mol, respectively. [ABSTRACT FROM AUTHOR] |
