High-resolution spectroscopy of C3 around 3 μm.

We report on the detection of the (10(0)1) ← (00(0)0) vibrational band of gas-phase C3 and the two of its mono (13)C substituted isotopologs in the infrared region around 3200 cm(-1). Additionally, the associated hot band (11(1)1) ← (01(1)0) has been assigned for the parent isotopolog. Spectra have been recorded using a supersonic jet spectrometer with a laser ablation source in combination with a continuous-wave optical parametric oscillator as radiation source. High-level quantum-chemical ab initio calculations have been performed and used to assist the assignment. A combined fit for the vibrational states of C3 found in this study has been done together with previously reported high-resolution data to increase the accuracy of the molecular parameters, especially for the ground state. The vibrational energies are 3260.126, 3205.593, and 3224.751 cm(-1) for the (10(0)1) state of C3, (12)C(13)C(12)C, and (13)C(12)C(12)C, respectively. The (11(1)1) state of C3 has been found to be at 3330.509 cm(-1).