Rotational spectra of 1-chloro-2-fluoroethylene. I. Main isotopologues and deuterated species of the trans isomer

Guided by theoretical predictions, the rotational spectra of the mono- and bideuterated species of trans-1-chloro-2-fluoroethylene, (CHCl)-Cl-35 = CDF, (CHCl)-Cl-37 = CDF, (CDCl)-Cl-35 = CHF, (CDCl)-Cl-37 = CHF, (CDCl)-Cl-35 = CDF, and (CDCl)-Cl-37 = CDF, have been recorded for the first time. Assignment of the Delta J=0 and Delta K-1=+1 bands with K-1=3,4,5,... (all isotopic species) as well as of several Delta J=+/- 1 and Delta K-1=+1 transitions (all isotopic species except (CHCl)-Cl-37 = CDF, (CDCl)-Cl-37 = CHF, and (CDCl)-Cl-37 = CDF) led to the accurate determination of the ground-state rotational constants, the quartic, and some sextic centrifugal distortion constants, as well as the nuclear quadrupole coupling constants for both Cl-35 and Cl-37 in good agreement with corresponding theoretical predictions based on high-level coupled-cluster calculations. Inconsistencies of the present spectroscopic parameters with respect to those reported earlier for the two main isotopologues, i.e., (CHCl)-Cl-35 = CHF and (CHCl)-Cl-37 = CHF, necessitated a reinvestigation of the rotational spectra for these two isotopic species. Supported by quantum chemical calculations, the previously recorded spectra are reassigned to a vibrationally excited state, while analysis of the Delta J=0 and Delta K-1=+1 as well as some Delta J=+/- 1 and Delta K-1=+1 transitions provided a revised set of spectroscopic parameters for the vibrational ground state of these two isotopic species. (c) 2006 American Institute of Physics.