Rotational spectrum and properties of the hydrogen-bonded dimer CH3CN⋯HCN

Abstract

Pulsed-nozzle, Fourier-transform microwave spectroscopy has been used to detect and measure the rotational spectra generated by three isotopic varieties of a hydrogen-bonded dimer formed between methyl cyanide and hydrogen cyanide. The observed spectra were characteristic of the ground state of a symmetric-top molecule and on analysis led to the following rotational constants B₀, the centrifugal distortion constants D_J and D_JK, and the ¹⁴N-nuclear quadrupole coupling constants χ(¹⁴N): [graphic omitted]. These spectroscopic constants allow the conclusion that the dimer has C_3ν symmetry with the arrangement H₃CCN⋯HCN of the nuclei. For the species CH₃C¹⁴N⋯HC¹⁵N, r(N⋯C)= 3.272 (2)Å and the hydrogen-bond stretching force constant k_σ= 9.51 (2) N m^–1.