Rotational spectra of isotopic furan-(argon)n, n=1,2, complexes and their vibrationally averaged structures

Article abstract of DOI:10.1016/0022-2860(94)08494-3

Pulsed nozzle Fourier transform microwave specroscopy has been used to observe the rotational spectrum of the furan-3,4-d2-(argon)2 van der Waaals complex.The rotational spectra of the furan-3-d-, furan-3,4-d2- and furan-d4-argon complexes have been measured in addition to the two previously measured isotopomers furan- and furan-2-d-argon.Rotational and quartic centrifugal distortion constants have been fitted for each isotopomer.Deuterium quadrupole coupling constants have been determined for the furan-3-d-argon complex from hyperfine splittings of the rotational transitions.A model considering the effects of large-amplitude van der Waals vibrations has been used for the determination of the intermolecular structural parameters.Argon has been located at a distance R=3.539(2) Angstroem from the center-of-mass of furan for the furan-argon complex.Argon has been found shifted towards the oxygen including an angle θ=9.7(2) deg between R and the principal axis c of furan.In the furan-(argon)2 complex, the two argon atoms assume symmetrical positions above and below the plane of furan with R and θ almost unchanged compared with the furan-argon complex.