Rovibrational Analysis of the nu(6) Bands of Four Symmetric Isotopomers of FClO(3)

High-resolution (ca. 5 x 10(-3) cm(-1)) infrared spectra of monoisotopic samples of F(35)Cl(16)O(3), F(37)Cl(16)O(3), F(35)Cl(18)O(3), and F(37)Cl(18)O(3) have been recorded in the region of the nu(6) fundamental band. This band is centered at 405.6055, 405.5097, 390.5406, and 390.4984 cm(-1), respectively. About 1000 nonzero-weighted transitions were fitted for each isotopomer with an isolated band model, obtaining a s.d. on the residuals close to the experimental precision. Three different reductions of the Hamiltonian have been tested and found almost equally good, although FClO(3) is a nearly spherical top molecule. Each includes the l(2, 2) interaction and either a d(t) DeltaK = +/-3 interaction term (reduction Q) an epsilon(t) DeltaK = +/-3 interaction term (reduction QD), or an l(2, -1) interaction (reduction D). Good agreement between the theoretical predictions for these reductions and the experimental data is observed. Copyright 1999 Academic Press.