LABORATORY MEASUREMENTS OF THE MILLIMETER-WAVE SPECTRA OF CALCIUM ISOCYANIDE

The 28 absorption features in the 130-170 GHz spectral region have bee n measured and assigned as fine-structure components of 14 pure rotati onal transitions of calcium isocyanide (CaNC) in its (0, 0, 0) X 2SIGM A+ state. The spectrum was analyzed using a standard Hamiltonian model for a linear molecule, and the resulting spectroscopic parameters wer e used to predict the transition frequencies and Einstein A-coefficien ts. The determined parameters are (in MHz) B = 4040.742(14), D = 4.96( 3) x 10(-3), H = 4.1(3) x 10(-7), L = -6.0(13) x 10(-11), M = 5.3(20) x 10(-15), gamma = 18.03(12), gamma(D) = -3.2(13) x 10(-5), where the numbers in parentheses are 3 sigma error estimates.