The rotational spectrum, H, 19F nuclear spin–nuclear spin coupling, D nuclear quadrupole coupling, and molecular geometry of a weakly bound dimer of carbon monoxide and hydrogen fluoride

Abstract

A dimer formed between carbon monoxide and hydrogen fluoride has been detected and identified in the gas phase through its rotational spectrum by using a pulsed Fourier transform microwave spectrometer equipped with a pulsed nozzle source of the dimers and a Fabry-Perot cavity. Rotational constants B0, centrifugal distortion constants DJ, deuterium nuclear quadrupole coupling constants χD, and the nuclear spin–nuclear spin coupling constants SHF and SDF for the vibrational ground state of each of the five isotopic species investigated are as follows (the errors in B0 and DJ are discussed in the text): These spectroscopic constants have been interpreted in terms of a linear equilbrium geometry in which the atoms are in the order OC⋅⋅⋅HF and in which the weak binding is therefore through a hydrogen bond to the carbon atom. Various quantities characterizing the intermolecular interaction potential have also been estimated from the above constants and are used with those similarly determined to make comparison both within the series OC⋅⋅⋅HX (X = F, Cl, and Br) and among the different series B⋅⋅⋅HX (B = Ar, Kr, OC; X = F, Cl, and Br).