Fourier transform infrared matrix and density functional theory study of the vibrational spectrum of the linear MgC3(-) anion.

The linear MgC(3)(-) anion has been identified in the products from the dual Nd:YAG laser ablation of carbon and magnesium rods trapped in solid Ar at ∼12 K. Measurements of (13)C isotopic shifts confirm the identification of the ν(1)(σ) vibrational fundamental at 1797.5 cm(-1). A second fundamental ν(2)(σ) has been tentatively identified at 1190.1 cm(-1). The results are in good agreement with the predictions of density functional theory calculations using the B3LYP functional with the 6-311+G(d) basis set. This is the first optical detection of the linear isomer of MgC(3)(-).