Analysis of the mm- and submm-wave rotational spectra of isotopic cyanamide: New isotopologues and molecular geometry

The rotational spectrum of cyanamide recorded for deuterated cyanamide at frequencies from 118 to 649GHz, and more limited spectra for isotopically enriched H2N13CN and H215NC15N were subjected to a detailed analysis using Loomis–Wood type graphical assignment techniques. Transitions in the lowest inversion doublet of 0+ and 0− substates were assigned for six new isotopic species: D2N13CN, HDN13CN, HD15NCN, HDNC15N, H2N13CN, and H215NC15N. The data for four other species, D215NCN, D2NC15N, H215NCN, and H2NC15N have been considerably extended. Spectroscopic constants and the inversion splitting have been determined for all of these species from a coupled fit of the two substates. Rotational constants for all known isotopic species of cyanamide have been combined with vibration–rotation constants obtained from an ab initio calculation in an evaluation of the reSE geometry of this molecule.