Isotopic Study of New Fundamentals and Combination Bands of Linear C5, C7, and C9 in Solid Ar

A high yield of carbon chains has been produced by the laser ablation of carbon rods having C-13 enrichment. FTIR spectroscopy of these molecules trapped in solid Ar has resulted in the identification of two new combination bands for linear C-5 and C-9. The (v(1) + v(4)) combination band of linear C-5 has been observed at 3388.8 cm(-1), and comparison of C-13 isotopic shift measurements with the predictions of density functional theory calculations (DFT) at the B3LYP/cc-pVDZ level makes possible the assignment of the v(1)(sigma(+)(g)) stretching fundamental at 1946 cm(-1). Similarly, the observation of the (v(2) + v(7)) combination band of linear C-9 at 3471.8 cm(-1) enables the assignment of the v(2)(sigma(+)(g)) stretching fundamental at 1871 cm(-1). The third and weakest of the infrared stretching fundamentals of linear C-7, the v(6)(sigma(+)(u)) fundamental at 1100.1 cm(-1), has also been assigned.