HF ... Cl_2. Bending dynamics of an antihydrogen-bonded van der Waals dimer

Abstract

The Π-bending fundamental of the HF…Cl_2 complex has been observed at high resolution near 33 cm^(−1), yielding a vibrational energy separation and rotational and nuclear quadrupole coupling constants. From these, estimates of the van der Waals stretching and Σ-bending frequencies are made, and a quartic—quadratic potential is fit to the data, with a barrier of 48 cm^(−1) to the linear H-F…Cl-Cl conformation. HF…Cl_2 is decidedly quasilinear, and the consequences of the flat θ_(HF) bending coordinate are discussed as they relate to the interpretation of recent photo-initiated bimolecular reactions HX…Y_2 → X + Y_2 → XY + Y.

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