The rotational spectra of the HCCCNH+, NCCNH+, and CH3CNH+ ions

Abstract

The rotational spectra of the HCCCNH + , NCCNH + , and CH 3 CNH + ions have been observed in a supersonic molecular beam by Fourier transformmicrowave (FTM) spectroscopy. The rotational and centrifugal distortion constants were determined for all three, and the nitrogen quadrupole hyperfine coupling constants for HCCCNH + and NCCNH + . From the respective Doppler shifts, it is found that the velocities of the ions are 3% larger than those of the parent unprotonated molecules, and the linewidths are greater by about 50%. The concentration of the ions near the nozzle is approximately 10 11 cm −3 , which is sufficiently high to be detectable in the visible and the IR by present laser techniques.