The microwave and millimeter wave spectrum of difluoromethanimine, F 2CNH: rotational and nuclear hyperfine structure analysis

Abstract

The rotational b-type spectrum of difluoromethanimine, F 2CNH, has been recorded for the first time between 15 to 40 GHz and 100 to 210 GHz. Some weak a-type transitions were also observed. From an analysis of the nuclear quadrupole hyperfine structure of the rotational transitions, quadrupole coupling constants for the 14N nucleus have been determined. Using Watson's A-reduced Hamiltonian in the I r-representation, the rotational constants and the quartic and sextic centrifugal distortion constants have been obtained for the ground vibrational state. The rotational constants are A = 11 464.02382(54) MHz, B = 11 151.89094(53) MHz and C = 5643.14072(47) MHz; the nuclear quadrupole coupling constants were determined to be χ aa = 0.968(5) MHz and (χ bb –χ cc ) = −3.995(9) MHz. The dipole moment along the b-axis could be determined from the frequency shift of the M J = 0 Stark component of the 1 1,1 ← 0 0,0 transition to be μ b = 6.004(24) × 10 −30 Cm (1.800(73) D).