TERAHERTZ ROTATIONAL SPECTRUM OF H2S

The rotational transition Frequencies of H2S in the terahertz region were measured precisely up to 1.08 THz by a BWO-based scanning spectrometer at Cologne, Germany, and up to 2.56 THz by a laser sideband spectrometer at Lille, France. The data obtained were analyzed together with the available mmW, sub-mmW, and FIR data using the Watson-type Hamiltonian with the power series expansion of 35 parameters up to J(10) terms and with the Pade approximation of 24 parameters up to J(8) terms. The results of the two different fits are compared and discussed. The present measurements are compared with those obtained with a FTIR spectrometer at its low-frequency limit, for the purpose of providing H2S lines in the terahertz region as an absolute calibrator for FIR FT spectroscopy. (C) 1995 Academic Press, Inc.