QUENCHING OF NH ND(B(1)SIGMA(+)) BY H-2, D-2 AND N-2 AT DIFFERENT TEMPERATURES AND PRESSURES/

The quenching of metastable NH/ND(b(1) Sigma(+)) radicals by Q = N-2, H-2 and D-2 has been studied using the pulsed VUV photolysis of NH3 fo r the generation, and the phosphorescence NH/ND(b(1) Sigma(+) --> X-3 Sigma(-)) for the time resolved detection of NH/ND(b). Quenching rate constants were obtained in the temperature range 200-440 K and pressur es of the bath gas N-2 or Ar were varied from 0.66 to 30 kPa. The aim of this investigation is to search for the formation of complexes and their stabilization during the quenching process. The rate constants f or Q = H-2 and D-2 suggest that complexes are formed which, however, a re not stabilized at Ar pressures up to about 30 kPa. The results will be discussed also with regard to sparse theoretical calculations.