High-resolution stimulated Raman spectroscopy and analysis of the ν₁ band of osmium tetroxide

We present the first high-resolution stimulated Raman study of osmium tetroxide (OsO₄). Lines from the ν₁ totally symmetric stretching fundamental have been assigned. These data together with the infrared assignments of the ν₃ band previously recorded (M. Louviot et al., J. Quant. Spectrosc. Radiat. Transfer, 2012, 113, 119–127) allowed a refinement of the analysis of the ν₁/ν₃ stretching dyad. We found that the ν₁ band has an unusual positive isotopic shift of approximately 0.32 cm^− 1/amu, which gives further evidence that the stretching dyad should be perturbed by a complex nearby bending band polyad. This work is part of a global effort to analyze all fundamental bands of OsO₄ to obtain a more precise experimental value of the ground state bond length for this heavy metal-containing molecule. The result could serve as a benchmark for high-level quantum chemistry calculations. Copyright © 2012 John Wiley & Sons, Ltd.