Radiofrequency, centimeter-, millimeter- and submillimeterwave spectra of PF3 in the nu(4)=1 vibrational state

Rotational spectra of PF3 in the degenerate vibrational state nu(4) = 1 hav e been measured in the radiofrequency, centimeter-, millimeter- and submill imeterwave range. 157 rotational transitions obeying the selection rules De lta J = 1, Delta k = Delta l = 0 have been observed in the range 100-900 GH z for 9 less than or equal to J less than or equal to 57 and 0 less than or equal to k less than or equal to 37, The J = 1 <-- 0 transition and 246 di rect l-type resonance transitions (Delta l = Delta k = +/-2) with values of J from 16 to 75 and G = \ k - l \ up to 74 have been measured using wavegu ide microwave Fourier transform spectroscopy in the range 8-26.5 GHz. Due t o an accidental degeneracy of the kl = -1 and 2 levels it was possible to o bserve for J = 17 and 18 Delta(k - l) = 3 'perturbarion-allowed' transition s with selection rules kl = 0 <-- -1 and kl = 2 <-- 3. in addition, A(1)-A( 2) splittings with kl = -2 and 4 have been measured for J = 25-29 in the ra diofrequency range using the technique of two-dimensional radiofrequency-mi crowave double-resonance Fourier transform spectroscopy. The data were anal ysed using the three reduced forms of the effective Hamiltonian [E.I. Lobod enko et al,, J. Mel. Spectrosc. 126 (1987) 159; H. Harder, J. Mel. Spectros c, 194 (1999) 145]. Parameters up to seventh order are accurately determine d and the unitary equivalence of the three parameter sets is demonstrated. (C) 2000 Elsevier Science B.V. All rights reserved.