Kinetic isotope effects in the quenching of NH(b 1Σ+) and of ND(b 1Σ+) by some deuterated compounds

Abstract

In addition to previous measurements with nondeuterated compounds, absolute rate constants for the quenching of metastable NH(b 1Σ+) and of metastable ND(b 1Σ+) radicals by HD, D2, D2O, CD4, C2D2, and C2D4 were determined at 296 K. The metastable NH and ND radicals were generated by pulsed vacuum uv photolysis of NH3 and of ND3 and were monitored by their (b 1Σ+; v′=0→X 3Σ−; v″=0) emissions at 471 nm. Large isotope ratios of the rate constants were measured for the quenching by hydrogenated and deuterated compounds.