The rotational spectrum of cobalt mononitrosyl (CoNO) produced by ultraviolet photolysis of Co(CO)3NO was observed in the millimeter-wave region. Seven rotational transitions in the ground state ranging from J=6-5 to 12-11, with hyperfine splittings due to the Co nucleus (I=7/2), were detected in a supersonic jet environment, while higher-frequency transitions in the range from J=29-28 to 35-34 were measured in the ground, ν1, ν2, ν3, and 2 ν2 vibrational states using a free-space absorption cell. It was confirmed from the observed spectral pattern that the CoNO molecule has a linear structure with the electronic ground state of 1∑+ symmetry. The rotational lines in the 2 ν2(∑) and ν3 states were observed to be perturbed by Fermi resonance. The equilibrium rotational constant Be is determined to be 4682.207(15) MHz. The CoN bond length is derived to be 1.5842 Å assuming the NO bond length of 1.1823 Å. A large nuclear spin-rotation interaction constant, CI =123.8 (11) kHz, was determined, suggesting a 1Π electronic excited state lying close to the ground state.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry