Conformational Space of 3-Chloropropionic Acid in Gas Phase Explored by Rotational Spectroscopy
Year: 2024
Type: article
Abstract: The conformational space of 3-chloropropionic acid has been studied under the isolated conditions of a supersonic expansion using Stark-modulated free-jet absorption millimeter-wave and centimeter-wave chirped-pulse Fourier transform microwave spectroscopy techniques. The rotational spectra originating from the three most stable conformers including 35 Cl and 37 Cl isotopologues were observed in both experiments using helium expansion while a partial conformational relaxation involving skeletal rearrangements takes place in an argon expansion. The rotational parameters, geometries, and energy order were determined from the experiment, allowing a comparison with quantum chemical predictions. B3LYP-D3(BJ)/def2-TZVP performs slightly better than MP2/aug-cc-pVTZ in reproducing the molecular geometries. The deviations are largerfor conformers showing intramolecular interactions. It is also shown that the Douglas–Kroll–Hess second-order scalar relativistic core Hamiltonian approach in the point nuclear approximation is needed to accurately reproduce the electronic properties encoded in the fully determined nuclear quadrupole coupling constant tensors.
Authors: Fufei Sun, Assimo Maris, Luca Evangelisti, Wentao Song, Sonia Melandri, J. Ricardo Morán, Camilla Calabrese, Alberto Lesarri
Institutions: University of Bologna, Universidad de Valladolid
Language: English
Subfield: Spectroscopy
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4405795454