EXPERIMENTAL SEPARATION OF TORSIONAL AND CHARGE REDISTRIBUTION EFFECTS IN ROTATIONAL SPECTRA OF HCN DIMERS

Abstract

Boand Djhave been determined for H13C15N-HC15N, HC15N-H13C15N, HC15N-DC14N and DC13N-HC15N. From them and other, previous results a full substitution structure has been obtained for HCN(1)-HCN(2). It leads to torsional amplitudes θ1 and θ2 of 13.6 and 9.3° for the two monomers in the dimer. A determination by fitting Bo for six isotopic species gives 13.7 and 8.7°. These values are used to separate torsional and charge redistribution effects upon the hyperfine interactions of 14N and D in the dimers. For 14N, about 40% of the difference in χa between HCN monomer and dimer is caused by charge redistribution. The C-D bond length in the dimer is considered.