Rotational spectrum and structure of 2-chlorothiophene and its complex with argon

2-chlorothiophene and its van der Waals complex with argon were studied by supersonic-jet Fourier transform microwave spectroscopy. Rotational measurements of parent and the mono-substituted ³⁷Cl, ³⁴S and ¹³C isotopologues of the monomer allowed its precisely structural determination. Rotational spectra of ³⁵Cl and ³⁷Cl isotopologues were observed and assigned for the van der Waals complex of 2-chlorothiophene with Ar. Ab initio calculations carried out at the MP2/6-311++G(d,p) level of theory complement the experimental studies. Spectroscopic and theoretical results support a conformation in which the Ar atom locates above the plane of aromatic ring and toward the substituted carbon atom. The distance between the centers of mass of 2-chlorothiophene and argon is 3.589 Å. The Non-Covalent Interaction analysis and Symmetry-Adapted Perturbation theory were performed to reveal the nature of the non-covalent interaction within the complex.