15min:

T. AMANO, M. NEZU AND Z. ZELINGER, Institute for Astrophysics and Planetary Sciences, Ibaraki University, Mito, Japan 310-8512.

We demonstrated that HNC produced in an extended negative glow discharge from a gas mixture of CH₄ and N₂ exhibited the same magnetic field dependence as ionic species, and we concluded that HNC was produced predominantly through a dissociative recombination reaction of HCNH⁺ with electrons. Okabayashi and Tanimoto observed the transitions up to J=4-3 for all the vibrational fundamentals as well as for the ground state. They found that the vibrational temperature was 230 K for the ₂ state, while those for the ₁ and ₃ modes were 1300-1600 K in a glow discharge in a mixture of CH₃CN and He. In our extended negative glow discharge, the vibrational temperature was found to be about 1500 K with no distinction among the vibrational modes. We extended the measurements to higher-J(up to J=7 6) and higher vibrational excited states using frequency-magnetic field double modulation technique. An extensive analysis was performed, in particular, for higher bending vibrational states. We will discuss implication of our observation to the branching ratio of the dissociative recombination reaction of HCNH⁺.