The Rotational Spectrum of CBrClF2 (Halon BCF): II. The Lowest Excited Vibrational States and Nuclear Quadrupole Coupling Tensors.

The analysis of the millimeter-wave rotational spectrum of the well-known halon molecule CBrClF2 was extended to rotational transitions in the excited vibrational states v9 = 1 (307 cm-1) and v5 = 1 (337 cm-1). The two states are appreciably coupled by a- and b-axis Coriolis interaction which was treated explicitly and spectroscopic constants were determined from measurements at frequencies from 121 to 330 GHz and J" from 18 to 111. The present work, together with our previous study (1996. J. Mol. Spectrosc. 177, 240-250), results in accurate constants in the rotational Hamiltonian for the four lowest vibrational states of C79Br35ClF2 and C81Br35ClF2. The double nucleus hyperfine structure in low-J transitions of the two 35Cl isotopomers of CBrClF2 was also measured in the region 3-14 GHz with a supersonic beam, cavity Fourier transform microwave spectrometer. All constants in both the inertial and the principal nuclear quadrupole coupling tensors have been determined for both Br and Cl nuclei. Copyright 1997 Academic Press. Copyright 1997Academic Press