The rotational spectrum,14Nhyphen;nuclear quadrupole coupling constants, and H,19F nuclear spinndash;nuclear spin coupling constant of the cyanogenndash;hydrogen fluoride dimer

摘要

The microwave rotational spectra of four isotopic species of a linear dimer NCCNsdot;sdot;sdot;HF formed between cyanogen and hydrogen fluoride have been observed and analyzed to give vibrational gound state rotational constantsB0, centrifugal distortion constantsDJ, the14Nhyphen;nuclear quadrupole coupling constants khgr;(1) and khgr;(2), and the H,19F nuclear spinndash;nuclear spin coupling constantsSHFas follows: thinsp; thinsp; thinsp; thinsp; thinsp; thinsp; thinsp; thinsp; thinsp; thinsp; thinsp; thinsp; thinsp; thinsp; It is shown that khgr;(1)minus;khgr;(2), which is necessarily zero in free cyanogen, arises from electrical changes rather than zerohyphen;point vibrational changes that accompany dimer formation. The part of this quantity assigned to polarization of cyanogen by hydrogen fluoride is interpreted on the basis of the Townesndash;Dailey model in terms of a transfer of sim;0.02efrom N(1) to N(2) when HF approaches the latter atom along the molecular symmetry axis to form the dimer.