Microwave measurements of cobalt and nitrogen quadrupole coupling in Co(CO)3NO

Abstract
J=2→3, 3→4, 4→5, and 5→6 transitions in the oblate symmetric top molecule cobalt tricarbonyl nitrosyl were measured using a Flygare–Balle type pulsed beam microwave spectrometer. K=0 and K=3 transitions were observed for J=3→4 and 4→5. Hyperfine structure due to 59Co and 14N nuclear quadrupole coupling interactions was well resolved. The measured quadrupole coupling strengths are eQqcc (59Co)=35.14(30) MHz and eQqcc (14N)=−1.59(10). Measured rotation and distortion constants are B0=1042.1590(4) MHz and Dj =0.17(8) kHz. The measured B value is 4% smaller than the B value calculated from electron diffraction data. Spin–rotation and a quadrupole distortion term were also obtained for 59Co.