On the stretching vibrations of linear C13: A coupled cluster study

The quadratic stretching force constants and the harmonic stretching vibrations of linear C13 have been studied by the coupled cluster variant CCSD(T) in conjunction with large basis sets. A large absolute IR intensity of 22,218 km mol−1 is calculated for the ν9 band. In comparison with a high-resolution spectroscopic study [T.F. Giesen, A. van Orden, H.J. Hwang, R.S. Fellers, R.A. Provencal, R.J. Saykally, Science 265 (1994) 756], the corresponding wavenumber experiences an unusually large anharmonicity contribution of 7%.