LABORATORY DETECTION OF THE C_9H RADICAL

摘要

The linear carbon chain radical C_9H in its ~2Π_(1/2) electronic ground state has been detected in a Fourier transform microwave spectrometer with a supersonic pulsed-jet discharge nozzle. The frequencies of 44 rotational transitions between 5.4 and 16.1 GHz have been measured to a few parts in 10~7, from which precise values for the rotational, centrifugal distortion, lambda doubling, and hyperfine constants have been determined. These allow calculation of the entire radio spectrum of the ground state of C_9H to a fraction of 1 km s~(-1) in equivalent radial velocity.