Microwave spectroscopy of carbonyl sulfide isotopologues solvated with 2-5 para-hydrogen molecules

We report high resolution Fourier transform microwave spectra of (pH(2))(N)-(OCS)-S-32 and (pH(2))(N)-(OCS)-S-34 clusters in the size range from N = 2 to 5. Observation of the J =1-0 and J = 2-1 transitions allowed for determination of the rotational (B) and quartic distortion (D) constants for each N. Comparison with theory (Paesani et al., 2003) reveals that the predicted B values are of good quality (all within 100 MHz of the actual values), while the predicted D values are an order of magnitude too high. Results from linear molecule Kraitchman analyses for clusters with N <= 5 are consistent with theoretical calculations which suggest that the initial pH2 density accumulates in a donut ring about the carbon oxygen bond. (C) 2017 Elsevier Inc. All rights reserved.