SIMBAD references

The well-known "XCN" feature near 2167cm^–1 observed towards various low- and high-mass embedded protostars can be well matched with a feature produced by photolysis of astrophysical ice analogs containing CO and NH₃. An assignment of this laboratory XCN band to OCN^– was earlier proposed based on the correspondence in position and in the ¹³C and ¹⁵N isotopic shifts. We report here a further experimental study of this identification. First, the isotope shift of the XCN band obtained by irradiating ¹⁸O labelled ice samples equals 8.7±0.6cm^–1, in good agreement with OCN^–. Second, highly sensitive spectroscopy reveals three additional weak features which can be assigned to the OCN^– ion. Together with the earlier work, these results leave little doubt to the correctness of the identification of the laboratory XCN feature with OCN^–.