The structure of nitrous oxide tetramer from near infrared laser spectroscopy

High resolution infrared spectroscopy has been used in conjunction with ab initio calculations to determine for the first time the structure of the nitrous oxide tetramer. We observe a non-planar structure in which all four molecules are approximately parallel. The high symmetry of this system makes the spectral assignment straightforward. In fact, the ab initio calculations and experiment indicate that this system is very nearly a spherical top with rotational constants A″ = B″ = 0.0248 cm−1 and A′ = B′ = 0.02495 cm−1. The C rotational constant can only be roughly estimated to be 0.02 cm−1 from the relative intensities of the Q and P, R branches observed in this C-type band.