2026-10-13T11:38:45Z https://api.figshare.com/v2/oai

oai:figshare.com:article/34036712 2026-09-30T19:17:27Z category_1 category_4 category_24 category_272 category_873 category_39 category_734 portal_63 item_type_6 month_year_09_2026

Dense Low-Energy Landscapes of C₂H₆S₂ and their Implications for Interstellar Sulfur Chemistry Rafael Flores-Larrañaga (22905742) Luis Armando Gonzalez-Ortiz (19279037) Filiberto Ortíz-Chi (19279040) María Eugenia Castro (10046566) Francisco J. Melendez (12092780) Lisset Noriega (12092777) Gabriel Merino (1413124) Biophysics Biochemistry Evolutionary Biology Environmental Sciences not elsewhere classified Chemical Sciences not elsewhere classified Ecology Biological Sciences not elsewhere classified vpt2 calculations reproduce shallow torsional potentials mean absolute error diverse bonding patterns 57 local minima 38 ev ). 10 – 9 polysulfur organic species interstellar sulfur chemistry 6 </ sub 2 </ sub containing species whereas geminal thermodynamically accessible structural diversity stable structures oxygen analogues narrow interval molecular inventory level jun global minimum ethyl hydrodisulfide energy landscapes dimethyl disulfide dependent populations containing structures conformational flexibility approximately 0 The molecular inventory of sulfur-containing species in the interstellar medium remains poorly constrained, particularly for polysulfur organic species. Here, a comprehensive ab initio exploration of the C₂H₆S₂ potential energy surface reveals a dense low-energy region containing numerous sulfur-containing structures with diverse bonding patterns and conformational flexibility. High-level jun-ChS + VPT2 calculations reproduce the available experimental rotational constants with a mean absolute error of approximately 0.2%, providing reliable spectroscopic reference data for future laboratory spectroscopic investigations. A total of 57 local minima were identified, including seven isomers within 30 kcal·mol^–1 of the global minimum. Ethyl hydrodisulfide and dimethyl disulfide are the most stable structures, whereas geminal and vicinal dithiols remain nearly degenerate, suggesting that several neutral isomers may be thermodynamically accessible. In contrast to their oxygen analogues, the low-energy sulfur isomers exhibit strong energetic crowding and shallow torsional potentials, generating large conformational manifolds with temperature-dependent populations. Despite this structural diversity, computed ionization potentials remain confined to a narrow interval (8.10–9.38 eV). 2026-09-30T00:00:00Z Text Journal contribution 10.1021/acsearthspacechem.6c00143.s002 https://figshare.com/articles/journal_contribution/Dense_Low-Energy_Landscapes_of_C_sub_2_sub_H_sub_6_sub_S_sub_2_sub_and_their_Implications_for_Interstellar_Sulfur_Chemistry/34036712 CC BY-NC 4.0