PNNL

Abstract

Further analysis of the high-resolution (0.0015 cm-1) infrared spectrum of 32S16 O3 has led to the assignment of more than 3,100 hot band transitions from v2 and v4 levels to the states 2v2 (l=0), v2+v4 (l=1), and 2v4 (l=0, 2). These leve ls are strongly coupled via Fermi resonance and indirect Coriolis interactions t o the v1 levels which are IR-inaccessible from the ground state. The unraveling of these interactions has allowed for the solution of the unusual and complicat ed structure of the v1 CARS spectrum. This has been accomplished by locating ov er 400 hot-band transitions to levels that contain at least 10% v1 character. T he complex CARS spectrum results from a large number of avoided energy level cro ssings between these states. Accurate rovibrational constants are deduced for a ll the mixed states for the first time, leading to deperturbed values of 1064.924(11), 0.000 840 93(64), and 0.000 418 19(58) cm-1 for v1, a1B, and a1C, respect ively. The uncertainties in the last digits are shown in parentheses and repres ent two standard deviations. In addition, new values for some of the anharmonic ity constants have been obtained. Highly accurate values for the equilibrium ro tational constants Be and Ce are deduced, yielding independent, nearly identical determinations of the SO re bond length of 141.734 03(9) and 141.732 54(13) pm, respectively.