title: The σ-hole interaction between sulfur hexafluoride and ammonia characterised by broadband rotational spectroscopy.
abstract: A weakly-bound complex of SF6 and NH3 is generated within an expanding gas jet and characterised by broadband rotational spectroscopy. The spectra of isotopologues (32) SF6 ⋅⋅⋅(14) NH3 , (32) SF6 ⋅⋅⋅(14) ND3 , (32) SF6 ⋅⋅⋅(15) NH3 and (34) SF6 ⋅⋅⋅(15) NH3 are observed and assigned to determine the spectroscopic parameters. These parameters are consistent with the complex having a C3v symmetric rotor geometry, in which the nitrogen atom of NH3 coordinates to SF6 such that the C3v axis of the NH3 sub-unit is aligned with a local C3 axis on the SF6 sub-unit. The geometry of the complex is rationalized in terms of a σ-hole interaction. The observed spectra and ab initio calculations also reveal evidence of internal dynamics involving internal rotation of one monomer sub-unit with respect to the other about the symmetry axis of the complex.
authors.affiliation: School of Chemistry, Bedson Building, Newcastle University, Newcastle upon Tyne, Tyne and Wear, NE1 7RU (U.K.).
authors.forename: Dror M
authors.initials: DM
authors.lastname: Bittner
authors.affiliation: School of Chemistry, Bedson Building, Newcastle University, Newcastle upon Tyne, Tyne and Wear, NE1 7RU (U.K.).
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Zaleski
authors.affiliation: School of Chemistry, Bedson Building, Newcastle University, Newcastle upon Tyne, Tyne and Wear, NE1 7RU (U.K.).|Current address: Chemistry Department, 360 Parker Building, University of Manitoba, Winnipeg, MB, R3T 2N2 (Canada).
authors.forename: Susanna L
authors.initials: SL
authors.lastname: Stephens
authors.affiliation: School of Chemistry, Bedson Building, Newcastle University, Newcastle upon Tyne, Tyne and Wear, NE1 7RU (U.K.). nick.walker@newcastle.ac.uk.
authors.forename: Nicholas R
authors.initials: NR
authors.lastname: Walker
authors.affiliation: School of Chemistry, University of Bristol, Bristol, BS8 1TS (U.K.). a.c.legon@bristol.ac.uk.
authors.forename: Anthony C
authors.initials: AC
authors.lastname: Legon
keywords: chirped-pulse fourier transform microwave; noncovalent interactions; rotational spectroscopy; sulfur hexafluoride; σ holes