Open positions:
PhD position
Presently, a PhD position is open on the project “Intermolecular interactions under control”
Intermolecular interactions are more often than not responsible for the functioning of synthetic and biological materials. Yet, fundamental studies in which these interactions are controllably tuned to elucidate on a molecular level how they influence structure and function are notoriously lacking. In this project we will investigate their role in two applications, one associated with the European Community Specific Targeted REsearch Project (STREP) project “Switchable materials and their fabrication technology for Multifunctional TAG” (STAG), and one associated with photoactive proteins. Aim of the STAG project is to devise new functional systems that are responsive to exposure to a temperature above a threshold value and/or exposure to UV light. One of the approaches employed in the project is based on discotic liquid crystals. The spectroscopic properties of the employed molecular systems have been studied to some extent in solution, liquid, and solid state, but the excited and ionic state properties under isolated conditions, and - in particular how they change upon aggregation - are largely unknown. Intermolecular interactions similarly dominantly determine how photoactive proteins like PYP and GFP function as has become amply clear from studies in solution. Under such conditions, one does, however, not have control over such intermolecular interactions. Spectroscopic studies of the structure and of the excited states of the neutral and ionic forms of representative chromophores under isolated conditions, in combination with studies in which the chromophore is controllably solvated can therefore be considered the key to genuinely understand the role of the protein matrix and of the solvent.
Job description
The candidate will set up, carry out, and interpret experiments in which the structure, spectroscopy, and dynamics of monomers, aggregates, and size-selected clusters with appropriate solvents of the relevant molecular systems are investigated with high-resolution spectroscopic methods. We will employ laser desorption in combination with supersonic expansions to obtain isolated molecules and clusters with one or more solvent molecules, and use Resonance Enhanced MultiPhoton Ionisation (REMPI) methods to characterize them. The candidate will explore methods to modulate the intermolecular interactions to guide chromophores along well-defined paths on the potential energy surface. A unique aspect of the research is the accessibility to the Free-Electron Laser for Infrared eXperiments (FELIX) facility in Rijnhuizen that allows us to cover the vibrational frequency region down to 40 cm-1.
The project is financed partially by the European Community, partially by the FOM Institute at Rijnhuizen. It will be carried out at the FOM Institute at Rijnhuizen and at the University of Amsterdam. We are looking for an enthusiastic candidate with a strong background in experimental physics or physical chemistry. Experience with lasers is an advantage, but not explicitly required.
For further information please contact:
Prof. Wybren Jan Buma (UvA),
Phone:+31-20-525 6973/6421
or
Dr. J. Oomens (FOM Rijnhuizen), Phone +31-30-6096999
PhD position
The Mechanics of Molecular Machines
It is tempting to consider molecular machines as nanoscale versions of their macroscopic analogues. However, many macroscopic mechanical concepts no longer apply at a molecular level. For instance, the concept of friction becomes meaningless for a molecular machine, since the size of the solvent molecules causing the friction is comparable to that of the machine itself. Also, a molecular machine experiences interactions with the surrounding solvent that in many cases are comparable to the force driving the machine. This will give rise to a certain amount of unpredictability in the motion of molecular machines. At present, the nature of the mechanics of molecular machines is largely unknown. At the University of Amsterdam, we experimentally investigate the mechanical behaviour of prototypical molecular machines. In this project, financed by the Stichting voor Fundamenteel Onderzoek der Materie (FOM), we have a fully funded PhD position available.
Job description The candidate will carry out and interpret experiments in which the operation of a molecular machine is triggered by means of a UV trigger pulse, and the mechanical motions are followed in real time by means of time-resolved one- and two-dimensional infrared spectroscopy. In this way, it is possible to construct "movies" of working molecular machines, and to study their mechanical motions directly. The time scales, velocities and potential-energy landscapes involved in the motions will be determined, and on a more fundamental level, we want to find out to what extent the motion of molecular machines is deterministic. The candidate will also explore ways of modifying, and in particular optimizing, the predictability of the motion (for instance by varying the design of the machine), and investigate if it is possible to 'kick-start' a molecular machine by means of optically induced breaking of hydrogen bonds.
The project will be carried out at the University of Amsterdam, under the supervision of dr. SanderWoutersen and prof. Wybren Jan Buma. We are looking for an enthusiastic candidate with a strong background in experimental physics or physical chemistry. Experience with lasers is an advantage but not explicitly required.
For further information please contact:Dr. Sander Woutersen Phone:+31-20-525 7091
Prof. Wybren Jan Buma Phone:+31-20-525 6973/6421