Abstract of "C, H, O, & N Isotopic Studies of the 4.619 micron "XCN" Feature Produced by UV Photolysis.." M. P. Bernstein, S. A. Sandford, and L. J. Allamandola. In Press at The Astrophysical Journal. 542: 894-897, (2000)

To better understand the chemical species that gives rise to the 2165 cm^-1 (4.62 micron) "XCN" absorption feature seen towards embedded protostars such as W33A, we have performed laboratory studies using deuterium (²H) isotopic labelling. We report the observation of a small but significant deuterium isotope shift for "XCN" which demonstrates that the atomic motion(s) causing the "XCN" peak in the laboratory samples must involve hydrogen. We also report the results of ¹³C, ¹⁵N, and ¹⁸O labelling experiments which are consistent with previously reported values.