Examination of the structures,energetics, and vibrational frequencies of small sulfur-containing prototypical dimers, (H2S)2 and H2O/H2S |
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Authors: | Katelyn M Dreux Gregory S Tschumper |
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Institution: | Department of Chemistry and Biochemistry, University of Mississippi, University, Mississippi, 38677-1848 |
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Abstract: | The optimized geometries, vibrational frequencies, and dissociation energies from MP2 and CCSD(T) computations with large correlation consistent basis sets are reported for (H2S)2 and H2O/H2S. Anharmonic vibrational frequencies have also been computed with second-order vibrational perturbation theory (VPT2). As such, the fundamental frequencies, overtones, and combination bands reported in this study should also provide a useful road map for future spectroscopic studies of the simple but important heterogeneous H2O/H2S dimer in which the hydrogen bond donor and acceptor can interchange, leading to two unique minima with very similar energies. Near the CCSD(T) complete basis set limit, the HOH⋯SH2 configuration (H2O donor) lies only 0.2 kcal mol−1 below the HSH⋯OH2 structure (H2S donor). When the zero-point vibrational energy is included, however, the latter configuration becomes slightly lower in energy than the former by <0.1 kcal mol−1. © 2018 Wiley Periodicals, Inc. |
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Keywords: | hydrogen bonding dissociation energies anharmonic vibrational frequencies water/hydrogen sulfide homogeneous and heterogeneous dimers second-order vibrational perturbation theory (VPT2) |
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