ACETYLENE SPECTRA WITH A TUNABLE DIODE-LASER - (NU-4 + NU-5)0+-NU-41F Q BRANCHES OF (C2H2)-C-12 AND (CCH2)-C-12-C-13

The rotational structure of the Q branches of the (ν4 + ν5)0+-ν41f bands of 12C2H2 and 12C13CH2 at 13.7 μm has been observed in a natural sample of acetylene by using a tunable diode laser as a source in a high-resolution infrared grating spectrometer equipped with a precision grating drive. Altogether 23 lines from J = 6 to 28 for 12C2H2 and 15 lines from J = 6 to 20 for 12C13CH2 have been identified. The observed full width at half maximum of the resolved lines of these Q branches is very close to the calculated Doppler width. Molecular constants ν0 + B″, B′ - B″ - 2D″, D′ - D″, and H′ - H″ have been derived from the measured line positions of the rotational structure. © 1979.