Cherry picking molecules from the soup: Spatial separation of pyrrole and pyrrole-water clusters

29 January, 2019

We demonstrated the spatial separation of pyrrole-water1 clusters with practically 100 % purity from the other atomic and molecular species in a supersonically-expanded beam of pyrrole and traces of water seeded in high-pressure helium gas.

Artist's sketch of the experiment: The strong electric field created by two deflector electrodes, indicated by the chopsticks, was used to pick isolated pyrrole-water1 from the soup of particles.

Our work on spatial separation of pyrrole and pyrrole-water clusters was published in Chemical Physics Letters and selected as "Editor's choice" for the cover page of the journal issue. 

Preparation of the hydrogen bonded molecule-water clusters, resulting in microsolvated molecular systems, was performed by seeding traces of water in high-pressure helium gas. This led to the creation of a soup of particles, which included larger molecular clusters, water clusters, and seed-gas atoms. Cherry picking a molecular beam of pyrrole-water1 clusters with high purity of nearly 100 % was achieved by passing the molecular beam, with the soup of species, through the electrostatic deflector. 

Furthermore, the achieved rotational temperature of the separated molecular beam of pure pyrrole-water1 dimers was less than one Kelvin, which is very favorable for fixing the molecular system in space. Thus, these pure and cold microsolvated molecular species are very well suited for future experiments aiming at imaging the structure and dynamics of such molecular aggregates in the molecular from and with highest fidelity.

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