Structure and properties of the argon⋅acetylene van der Waals molecule

Abstract

Describing van der Waals Interaction in diatomic molecules with generalized gradient approximations: The role of the exchange functional Structure and properties of the argon-ozone van der Waals molecule Radio frequency spectroscopy and Stark effect measurements have been carried out on Ar·HCCH and Ar·DCCD produced in acetylene seeded argon beams. Because of the very small electric dipole moment, Il = 0.02697(3) D, only the 110-111 transition and low frequency pure Stark transitions were observed. Observations are only compartible with a T-shaped equilibrium structure with an Ar to acetylene distance of 3.25(I)A. Deuterium hyperfme data provide a 204.4(10) KHz value for eqQ of acetylene and arccos (v' <cos 2 0» = 72(1)' for the complex.

Experimental 2CH excitation in acetylene-containing van der Waals complexes

“…Experimentally, the C 2 H 2 -Ar van der Waals molecular complex has been studied in various spectral regions, including microwave [67][68][69], infrared [56,68,[70][71][72][73][74] and, as already mentioned, near-infrared [39].…”

Isotopic Study of Rotational Spectra of the Ar–Acetylene Complex

“…Evidence for a low angular anisotropy of the Ar-acetylene interaction was found in Refs. (1) and (3), where expectation values for the angle of 60°and 72°were derived from a D-nuclear quadrupole hyperfine analysis and from the A rotational constant, respectively. The corresponding values for Ar-CO 2 (16), a relatively rigid system, are 81.5°and 84.4°, while the value from a 14 N-nuclear quadrupole hyperfine analysis for the isoelectronic Ar-HCN (17), a highly nonrigid molecule with linear equilibrium geometry, is 59.2°.…”

“…It was first studied by DeLeon and Muenter, using the molecular beam electric resonance technique (1). The J Ka Kc ϭ 1 11 -1 10 transition was measured for both Ar-HCCH and Ar-DCCD.…”

Orientation dependence in collision induced electronic relaxation studied through van der Waals complexes with isomeric structures

“…The equilibrium structure of the So (1S~) ground state acetylene is linear, whereas that of the first excited singlet state $1 (1/7,) is trans-bent planar [41,42]. The ground state of the acetytene-Ar complex has been studied by molecular-beam electric resonance [44], FT-microwave [45], and IR [46,47] spectroscopy. All these studies have indicated that the complex has a T-shaped, C2~ s~(mmetry, structure with the Ar atom located about 4 A away from the center of mass mum.…”