Infrared laser spectroscopy of the nu(4) and nu(9) band system of (CH2FCl)-Cl-37

The spectra of (CH2FCl)-Cl-37 (95% isotopically pure sample) have been reco rded at high resolution with a tunable diode laser spectrometer in the regi ons 979-1030 and 1108-1136 cm(-1). The spectral analysis allowed us to assi gn about 2000 lines (J less than or equal to 61, K-a less than or equal to 26) of the nu(9) band (nu(o) = 1001.9360 cm(-1)), which, besides the expect ed c-type component, shows a more intense Coriolis-induced parallel compone nt deriving its intensity from mixing with the nu(4) vibrational state. In addition, the assignments of the nu(4) band (nu(o) = 1067.7138 cm(-1)), pre viously investigated, have been extended to higher K-a values and about 130 0 new lines (J less than or equal to 69, 17 less than or equal to K-a less than or equal to 26) have been identified. The nu(4) and nu(9) bands have b een fitted simultaneously to account for the first-order a- and b-type Cori olis coupling; interaction constants and excited state parameters up to the sextic terms have been obtained using Watson's A-reduction Hamiltonian in the 1(r) representation. (C) 1999 Academic Press.