40 absolute line wavenumbers in the 3 4 band of ''C'602 between 6927 cm-' and 6989 cm-' and 626 absolute line wavenumbers in the near infrared absorption spectrum of 12CzHz between 7060 cm-' and 9900 cm-' have been measured using high resolution Fourier transform spectroscopy. The calibration of the COz line wavenumbers relied on heterodyne frequencies available in the vI t z q band of 12C2H2 near 6556cm-'. The absolute uncertainty of the calibrated CO, line wavenumbers is estimated to 0.000 08 cm-' . The acetylene spectra were calibrated using heterodyne frequencies available in the 2 4 band of 12Clh0 and the line wavenumbers obtained in the 3v3 band of I2ClhO2. The absolute uncertainty of the calibrated acetylene line wavenumbers is estimated to range from 0.0003 cm-I to 0.006 cm-' for strong to very weak isolated lines. Comparison with absolute line wavenumbers obtained independently at JPL in the 3v3 band of I2C2H2 near 9649cm-', calibrated using absolute wavenumbers available in the 2 4 and 3 4 (near 6350cm-I) bands of '2C'60, shows very good agreement. Also, the vibration-rotation constants for the observed upper vibrational states of I'C2H2 were determined, but without accounting for the perturbations affecting these states.

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