## Abstract

An isolated complex of C _{2}H _{4} and ICF _{3} has been generated in the gas phase and studied by chirped-pulse, Fourier transform microwave (CP-FTMW) spectroscopy. Ab initio calculations at the CCSD(T)(F12)/VTZ level support the experimental work and further establish the dissociation energy, D _{e}, and dipole moment, μ, of the complex. Rotational constants, B _{0} and C _{0}, the centrifugal distortion constant, Δ _{J}, nuclear quadrupole coupling constants, χ _{aa} (I) and (χ _{bb}(I)-χ _{cc}(I)) and the nuclear spin-rotation coupling constant C _{bb}(I) of the complex are determined from the experimental data. The iodine atom interacts with π-electrons on C _{2}H _{4} resulting in the formation of a linear (∠(CI⋯)) halogen bond (where indicates the centre of the CC bond) and a complex of C _{s} symmetry. The measured rotational constants allow the length of the halogen bond to be determined as 3.434(2) Å in the r _{0} geometry. The complex is formally an asymmetric top but with a very low barrier to internal rotation of C _{2}H _{4} about the C _{3} axis defined by the CF _{3}I sub-unit. Adopting an approach also used in a recent study of H _{2}O⋯ICF _{3}, other transitions are assigned using the Hamiltonian of a symmetric top molecule.

Original language | English |
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Pages (from-to) | 47-53 |

Number of pages | 7 |

Journal | Journal of Molecular Spectroscopy |

Volume | 280 |

Issue number | 1 |

DOIs | |

Publication status | Published - Oct 1 2012 |

## All Science Journal Classification (ASJC) codes

- Atomic and Molecular Physics, and Optics
- Spectroscopy
- Physical and Theoretical Chemistry