Pulsed molecular cluster aggregation (PMCA)

A variety of metals, organic molecules and even biomolecules such as nucleotide bases, vitamins, vanillin or caffein, can be first evaporated of laser desorrbed and then entrained by an adiabatically expanding, cooling noble gas jet. In this dense plume they can aggregate to large van der Waals clusters. 

• We have observed tryptophan clusters up to Trp30  using VUV postionization TOF-MS mass spectrometry.
• Clusters of caffein and vanillin, generated by this method, have also been successfully used in OTIMA interferometry.