Internuclear distance and effects of Born-Oppenheimer breakdown for PtS, determined from its pure rotational spectrum

The internuclear distance and effects of Born-Oppenheimer breakdown for platinum monosulfide (PtS) were investigated using a cavity pulsed jet Fourier-transform microwave spectrometer. The spectral analysis using a multi-isotopomer Dunham-type expression produced values for Y₀₁, Y₀₂, Y₁₁, and Y₂₁, along with large values for Born-Oppenheimer breakdown (BOB) parameters for both atoms of the molecule. The BOB parameters were rationalized in terms of the molecular electronic structure and nuclear field shift effects. The equilibrium bond length was also evaluated along with the vibrational frequency and dissociation energy.