High resolution IR study of the van der Waals complexes of HCCCN with CO2 and N-2

The high resolution IR spectra of HCCCN-CO2 and HCCCN-N-2 have been studied using molecular beam optothermal spectroscopy. For both complexes, structural information has been obtained; HCCCN-CO2 has been determined to be T-shaped with the CO2 molecule at the N end of HCCCN, while N-2-HCCCN was found to be hydrogen-bonded in a linear configuration. Accurate molecular constants have been obtained. From the rotational constants, the van der Waals bond lengths of the two dimers have been determined assuming that the structure of the monomer units does not change upon complexation. The results are compared with those for the corresponding complexes Of HCN. (C) 1996 Academic Press, Inc.