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Aligning amphiphilic molecules on a water surface into large two-dimensional (2D) crystals by laser field

Final Activity Report Summary - ALIGNMENT-PROJECT (Aligning Amphiphilic Molecules on A Water Surface into Large Two-Dimensional (2D) Crystals by Laser Field)

This project focussed on the following two main objectives:

1. the alignment of amphiphilic molecules on a water surface into large two-dimensional crystals by a laser field and
2. on quantum state selection, alignment and orientation of molecules using static electric and laser fields.

Regarding the first objective, this was the research area defined in the original proposal. The main project finding was that large, polymer-like molecules, when spread out on a water surface, could be crystallised in ordered structures in case the surface was irradiated with intense light pulses from powerful laser sources. The studies were carried out on poly benzyl-L-glutamate and peptide alamethicin. The findings could have important influence on facilitating crystallisation of membrane proteins, molecular electronics and self-assembling of nanomaterials.

Regarding the second objective, the idea was to select gas-phase molecules in the lowest lying rotational states by means of a strong inhomogeneous static electric field, a so called molecular deflector. Building on ideas that went back to Otto Stern in the 1920s a molecular deflector was constructed through the collaboration of our group at Aarhus University and a group at the Fritz Haber Institute in Berlin. The quantum state selected molecules enabled unprecedented orientational control of various molecules using a combination of intense laser pulses and weak static electric fields. The results were anticipated to have profound consequences for x-ray diffraction studies at emerging free-electron laser sources, femtosecond time resolved reaction dynamics and strong field physics phenomena.