Knowledge Bank

A rotationally resolved near infrared spectrum of $(N2O)2$ has been obtained, corresponding to the $\nu 1\prime +\nu 3\prime$ band of the $N2O$ monomer using the molecular beam optothermal detection technique. The spectrum has been assigned to an asymmetric rigid rotor structure with both A-and B-type transitions present. From the nuclear spin statistics, arising from the nitrogen nuclei, and the ground state rotational constants, the structure of the dimer has been determined to be planar (offset anti-parallel) with $C2h$ symmetry. This is similar to the structure determined previously for $(CO2)2$. Local perturbations are observed in $Ka=0$ and 1 of the excited vibrational state. Further work is underway to completely assign the spectrum in an effort to understand the pattern and origin of the local perturbation. It is interesting to note that the dimer spectrum is shifted slightly to the red of the monomer origin while the larger clusters are observed to be blue shifted.