Rotational spectroscopic study of carbonyl sulfide solvated with hydrogen molecules

Abstract

Rotational spectra of small-sized (H(2))(N)-OCS clusters with N = 2-7 were measured using a pulsed-jet Fourier transform microwave spectrometer. These include spectra of pure (para-H(2))(N)-OCS clusters, pure (ortho-H(2))(N)-OCS clusters, and mixed ortho-H(2) and para-H(2) containing clusters. The rotational lines of ortho-H(2) molecules containing clusters show proton spin-proton spin hyperfine structure, and the pattern evolves as the number of ortho-H(2) molecules in the cluster increases. Various isotopologues of the clusters were investigated, including those with O(13)CS, OC(33)S, OC(34)S, and O(13)C(34)S. Nuclear quadrupole hyperfine structures of rotational transitions were observed for (33)S (nuclear spin quantum number I = 3/2) containing isotopologues. The (33)S nuclear quadrupole coupling constants are compared to the corresponding constant of the OCS monomer and those of the He(N)-OCS clusters. The assignment of the number of solvating hydrogen molecules N is supported by the analyses of the proton spin-proton spin hyperfine structures of the mixed clusters, the dependence of line intensities on sample conditions (pressure and concentrations), and the agreement of the (para-H(2))(N)-OCS and (ortho-H(2))(N)-OCS rotational constants with those from a previous infrared study [J. Tang and A. R. W. McKellar, J. Chem. Phys. 121, 3087 (2004)].

Molecular Superfluid: Nonclassical Rotations in DopedPara-Hydrogen Clusters

“…Simulation work predicted superfluidity for OCS-doped pH 2 clusters [10,11] with a turnaround of B at N ¼ 14. However, this prediction is not yet confirmed by experiment, since published measurements extend only to N ¼ 7 [12]. In other experiments, superfluidity was inferred for doped pH 2 clusters embedded in helium nanodroplets based on the behavior of the Q branch of the rovibrational spectrum [13][14][15][16].…”

Analytic Morse/long-range potential energy surfaces and predicted infrared spectra for CO–H2 dimer and frequency shifts of CO in (para-H2)N N = 1–20 clusters

“…In similar way, clusters of para-hydrogen (para H 2 ) molecules doped with a single chromophore molecule [22][23][24][25][26][27][28][29][30][31][32][33] are also considered as a possible route to investigate the superfluidity of para-hydrogen. Recently, combining experimental measurements and theoretical simulations, the non-classical rotational inertia and superfluid response in pure para H 2 clusters doped with CO 2 have been first elucidated.…”

Microscopic molecular superfluid response: theory and simulations

“…Although these studies were not dedicated to pH 2 superfluidity, they provided technical preparation for follow-up work. In 2008, Michaud and Jäger published the first MW study of doped H 2 clusters [102]. They used a pulsed-jet Fourier transform MW spectrometer to measure rotational spectra of OCS(pH 2 ) N and OCS(oH 2 ) N , with N = 2 − 7.…”