Precision measurements of acetylene spectra at 1.4-1.7 mu m recorded with 352.5-m pathlength

The spectrum of acetylene (C2H2) in the 1.5 mu m region has been recorded at room temperature with Doppler-broadening-limited resolution at pathlengths up to 352.5 m. The spectra were obtained by using an all vacuum Fourier transform infrared (FTIR) spectrometer with a multipass cell of 4 m base length attached to it. The calibration of the data is discussed in detail. Thirty-three subbands have been detected in this study for C2H2 and five for (CCH2)-C-12-C-13. These include ten new bands and nine new states in the parent species, and two new bands and two new states in the (CCH2)-C-12-C-13 species. Updated energy level diagrams for HCCH and (HCCH)-C-13 are shown. The spectroscopic constants obtained from the HCCH spectrum are reported. (C) 1996 Academic Press, Inc.