Dienstag, 26. August 2008

Ph.D. Students Physical Chemistry/Solid State NMR

Ph.D. Students Physical Chemistry/Solid State NMR

At present there are several vacancies for both phd projects and post doc positions.

1) Hydrogen storage

One of the critical problems for a future economy that is less dependent on fossil fuels is the need to find a suitable solution for energy storage. Hydrogen gas is considered as a promising candidate for a light and clean fuel in automotive applications. However the hydrogen density both in the liquid and (high pressure) gas phase is rather low. Storage of hydrogen in the form of complex chemical compounds such as metal hydrides can be an attractive alternative. Recent developments have shown that reversible hydrogen charging is possible at near ambient pressures and temperatures. However, the kinetics and thermodynamic efficiency need to be further optimized. Also, the effective weight of these compounds are still rather high. With solid state synthesis methods it is possible to make thin films with gradients in composition or catalytic doping. This can be used as an effective method of combinatorial chemistry to optimize the density and kinetics of the hydrogen storage.

NMR is the method of choice to study local molecular and (disordered) crystalline structure. Also, it can give insight in local mobility of the hydrogen atoms. Unfortunately the conventional NMR probes are not optimized for thin film samples and the relatively low sensitivity precludes high resolution MRI and local NMR spectroscopy. With new stripline rf stuctures we can achieve a much higher sensitivity. In addition, the planar design is optimal for thin film applications. It is the purpose of the present project to develop a novel type of scanning NMR probe that will be used for local analysis of these combinatorial hydrogen storage materials. If you are interested in a combination of fundamental science with innovative technological developments aimed at a solution for urgent environmental problems then this is the job for you.

2) Dynamic Nuclear Polarization on a chip

With modern microfluidic chip technology it is possible to do chemical synthesis in nanoliter volumes. We are developing NMR methods to be able to monitor these reactions in situ. This may allow a fast and convenient optimization of all process parameters. In addition, one can study the reaction kinetics in detail and intermediate products can be identified. A second application of this technology is the study of very small samples of for example human or animal metabolites. We have recently demonstrated that this is possible without loss in resolution. However, for these low concentration samples it is necessary to enhance the sensitivity of the NMR method. Since the probe designs already approach intrinsic quantum sensitivity limits, the only alternative is to enhance the effective polarization of the nuclei. This can be done by a transfer of the much larger polarization from unpaired electrons, thus effectively cooling the nuclei to a more favourable Bolzmann distribution.

We are looking for two enthousiastic and highly motivated PhD students to realize this possibility. One student will be based at the Mesa+ center at the university of Twente, and will concentrate on the design and production of the chips, including the necessary microwave structures. The second student will be based at the Radboud University and will concentrate on the NMR and EPR aspects. Applications of the new methodology to analyse bio metabolites will be a joint effort.

3) High sensitivity solid state NMR at 850 MHz

The infrastructure for solid state NMR at the Radboud University will soon be upgraded with a powerful 850 MHz wide bore NMR system. This will provide unique capabilities to study functionalized molecular materials. A continuous effort is to optimized the NMR sensitivity for these nanosized samples. We recently developed a novel MAS probe with integrated microcoil detection. This design opens new possibilities for ultra low temperature NMR. Also it can be combined with efficient microwave resonators to allow in situ high frequency Dynamic Nuclear Polarization. In collaboration with Varian inc. (one of the main suppliers of NMR spectrometers) we will develop the necessary equipment for this purpose. A novel gyrotron source will be built to provide the TeraHertz radiation for DNP.

We are looking for an experienced and creative postdoc, preferably with a background in NMR and/or TeraHerz spectroscopy. Excellent experimental and communication skills are required to make this international endeavor to a succes.


Required education/skills: Doctorate
We are looking for an enthusiastic researcher with a Master’s degree in physics or physical chemistry, and with adequate theoretical and experimental skills. We prefer candidates with a good team spirit, who like to work in an internationally oriented environment and are able to collaborate with our partner groups on the crossroads between chemistry and (technical) physics.

Conditions of employment

Estimated maximum salary per month: eur 2000 - 2500
Employment basis: Temporary for specified period
Duration of the contract for PhD studens: Starts for a period of
one year, with a possible prolongation till 4 years
Maximum hours per week: 40
The post-doc position is initially for a period of two years.
Salary will depend on previous expertise.

Additional information about the vacancies can be obtained from:

E-mail address: A.Kentgens@science.ru.nl

Or through one of the following links.

about the department

Radboud University Nijmegen