Effective rotation-vibration parameters for the ν8 and ν4+ν12 bands of ethane

The jet-cooled spectrum of ethane in the region of the nu(8) perpendicular fundamental vibration at 1472 cm(-1) was recorded with a Fourier transform spectrometer at 0.01 cm(-1) instrumental resolution. About 1150 lines were assigned to 18 subbands of nu(8) ranging from K "Delta K = -9 to +8. About 160 lines were assigned to three subbands (K "Delta K = 0 to +2) of the nu(4) + nu(12) combination band near 1481 cm(-1). Torsional splittings were observed for the majority of the transitions. A stack-by-stack analysis was performed, resulting in effective rovibrational parameters for the upper stares nu(8) and nu(4) + nu(12). A number of perturbations was observed and is discussed, (C) 1999 Academic Press.