title: Ring-Puckering Potential Energy Functions for Trimethylene Sulfide and Its Monovalent Cation.
abstract: The spectra and ring-puckering potential energy function for trimethylene sulfide cation (TMS+) from vacuum ultraviolet mass-analyzed threshold ionization spectra have recently been reported. To provide an in-depth comparison of the potential function with that of trimethylene sulfide (TMS) itself, we have used ab initio MP2/cc-pVTZ calculations and DFT B3LYP/cc-pVTZ calculations to predict the structures of both TMS and TMS+and then used these to calculate coordinate-dependent ring-puckering kinetic energy functions for both species. These kinetic energy functions allowed us to calculate refined potential energy functions of the puckering for both molecules based on the previously published spectra. TMS has an experimental barrier of 271 cm-1and energy minima at ring-puckering angles of ±29°. For TMS+the barrier is 60 cm-1and the energy minima correspond to ring-puckering angles of ±21°. The lower barrier for the cation reflects the smaller amount of angle strain in the ring angles for TMS+.
authors.affiliation: Department of Chemistry, Texas A&M University , College Station, Texas 77843-3255, United States.
authors.forename: Hye Jin
authors.initials: HJ
authors.lastname: Chun
authors.affiliation: Department of Chemistry, Texas A&M University , College Station, Texas 77843-3255, United States.
authors.forename: Esther J
authors.initials: EJ
authors.lastname: Ocola
authors.affiliation: Department of Chemistry, Texas A&M University , College Station, Texas 77843-3255, United States.
authors.forename: Jaan
authors.identifier: http://orcid.org/0000-0003-4423-6122
authors.initials: J
authors.lastname: Laane