GROUND-STATE RO-INVERSIONAL TRANSITIONS OF (NH3)-N-15 IN THE FAR-INFRARED REGION

The high-resolution FIR spectrum of (NH3)-N-15 has been measured in na tural abundance by the Fourier-transform spectrometer at Giessen, Germ any in the wavenumber range from 30 to 120 cm(-1). The accurate experi mental line positions (estimated error of 0.00006 cm(-1)) of the groun d state rotation-inversion transitions of this isotopomer, which have been obtained from a line profile analysis, were fitted by the effecti ve rotational Hamiltonian expressed in the conventional polynomial way , as well as in the Pade form. The high accuracy of the transition wav enumbers has been confirmed by the standard deviations of our fits of 0.000040 and 0.000038 cm(-1) obtained with the polynomial and Pade for ms, respectively. A better extrapolation capability of the Pade approx imant has been demonstrated. (C) 1994 Academic Press, Inc.