RESUMO
The pressure broadening, pressure shift coefficients, and absolute intensities have been obtained for the J = 6 <-- 5 and the J = 5 <-- 4 absorption lines of acetonitrile CH3CN at 110 and 92 GHz, respectively. The absorption line shapes have been directly recorded modulating the radiation beam by an optical chopper. In addition to the self-effects, the foreign-broadening coefficients have also been measured for N2, O2, and Ar. Copyright 1998 Academic Press.
RESUMO
A BWO-based terahertz spectrometer has been constructed and tested by measuring some high-J rotational transitions of NNO in the frequency region from 620 to 730 GHz. The observed line center frequencies confirm the previously reported ones obtained by FTIR spectroscopy. The high sensitivity of the present spectrometer allowed us to record spectra of singly substituted isotopomers, 15NNO, N15NO, NN18O, and NN17O, in natural abundance. The rotational and centrifugal distortion constants have been revised. Copyright 1997 Academic Press. Copyright 1997Academic Press