CO Aggregation on Monoethanolamine: Observations from Rotational Spectroscopy.

The initial stages of the gas-phase nucleation between CO and monoethanolamine were investigated via broadband rotational spectroscopy with the aid of extensive theoretical structure sampling. Sub-nanometer-scale aggregation patterns of monoethanolamine-(CO ) , n=1-4, were identified. An interesting competition between the monoethanolamine intramolecular hydrogen bond and the intermolecular interactions between monoethanolamine and CO upon cluster growth was discovered, revealing an intriguing CO binding priority to the hydroxyl group over the amine group. These findings are in sharp contrast to the general results for aqueous solutions. In the quinary complex, a cap-like CO tetramer was observed cooperatively surrounding the monoethanolamine. As the cluster approaches the critical size of new particle formation, the contribution of CO self-assembly to the overall stability increases.