Analysis of some combination-overtone infrared bands of 32S16O3

several new infrared absorption bands for (SO3)-S-32-O-16 have been measured and analyzed. The principal bands observed were v(1) + v(2) (at 1561 cm(-1)), v(1) + v(4) (at 1594 cm(-1)), v(3) +v(4) (at 1918 cm(-1)), and 3v(3) (at 4136 cm(-1)). Except for 3173, these bands Lire very complicated because of (a) the Coriolis Coupling between v(1) and v(4), (b) the Fermi resonance between v(1) and 2v(4), (c) the Fermi resonance between v(1) and 2v(2), (d) ordinary l-type resonance that couples levels that differ by 2 in both the k and l quantum numbers, and (e) the vibrational l-type resonance between the A(1)', and A(2)' levels of v(3) + v(4). The unraveling of the complex pattern of these bands was facilitated by a systematic approach to the understanding of the various interactions. Fortunately, previous work on the fundamentals permitted good estimates of many constants necessary to begin the assignments and the fit of' the measurements. In addition, the use of hot band transitions accompanying the v(3) band was an essential aid in fitting the v(3) + v(4) transitions since these could be directly observed for only one of four interacting states. From the hot band analysis we find that the A, vibrational level is 3.50 cm(-1) above the A(2)' level, i.e., r(34) = 1.75236(7) cm(-1). In the case of the 3v(3) band, the spectral analysis is straightforward and a weak Deltak = +/-Deltal(3) = +/-2 interaction between the l(3) = 1 and l(3) = 3 substates locates the latter A(1)' and A(2)' ghost states 22.55(4)cm(-1) higher than the infrared accessible l(3) = 1 E' state. (C) 2004 Elsevier Inc. All rights reserved.