15min:

JIAN TANG, YOSHIHIRO SUMIYOSHI AND YASUKI ENDO, Department of Basic Sciences, The University of Tokyo, Komaba, Tokyo 153-8902, Japan.

In contrast with that cyanopolyynes have been detected in laboratory up to HC₁₇N and in interstellar space up to HC₁₁N, our knowledge on the linear form of HC_nN with even n number has been limited to only the HCCN radical by laboratory detection and interstellar observation. We report here a detection of the HC₄N radical in its triplet electronic ground state in the discharge of HC₃N (0.2%) diluted in Ar. A Fourier-transform microwave spectrometer equipped with a pulsed-discharge nozzle\footnote Y.~Ohshima and Y.~Endo, J.~Mol.~Spectrosc. \underline\textbf153 627(1992). has been used. The combination of discharge mixtures, the rotational structure, and the fine and hyperfine structure that is similar to the HCCN radical all indicated that the carrier of the spectrum is HC₄N with linear or quasilinear structure. Progress on the characterization of this new radical will be presented.