THE HIGH-RESOLUTION FOURIER-TRANSFORM INFRARED-SPECTRUM OF ISOCYANOGEN, CNCN - ROVIBRATIONAL ANALYSIS OF THE NU(4), NU(5), AND NU(4)+NU(5) BAND SYSTEMS AND THE FERMI DYAD NU(3) AND 2-NU(4)

The high-resolution gas-phase Fourier transform infrared spectrum of the linear molecule isocyanogen, CNCN, has been measured between 150 and 1300 cm-1 with an unapodized resolution of 0.0018 cm-1. The band systems due to the excitation of the cis and trans bending modes ν5 and ν4 around 194.8 and 463.5 cm-1, respectively, have been analyzed. Additionally the combination band system ν5 and ν4 around 659.0 cm-1 and the transitions to the Fermi resonance pair ν3 and 2ν4 around 875 and 975 cm-1, respectively, were analyzed. Furthermore, two components of the related Fermi triad could be assigned. Constants of a power series in J(J + 1) for the numerous subbands as well as constants of an effective Hamiltonian. © 1993 Academic Press, Inc.