POSITIONS AVAILABLE
Positions for undergraduate students (“HiWi”) as well as master's projects are currently available. (Studentarbeit and Mastersarbeit projects are available at any time.)

Descriptions of the projects for which the positions are provided below. The schedule is flexible, with a schedule of up to 19 hours per week available. If you are interested in these positions, please contact Prof. Ismail directly at
ahmed.ismail@avt.rwth-aachen.de for further details.

Additionally, students can apply for
admission to the doctoral program in the AICES graduate school; these positions include a stipend that enables the student to pursue a research topic that has been selected in consultation with an AICES advisor.
PhD/Post-Doc positions are available for the following projects:
MOLECULAR SIMULATION OF BIOMASS DISSOLUTION
Our group, as part of the “Tailor-Made Fuels from Biomass” Cluster of Excellence at RWTH Aachen University, studies dissolution of lignocellulosic biomass using molecular simulations. This ranges from atomistic studies of cellulose dissolution in ionic liquids, reactive molecular dynamics of lignin dissolution, and kinetic Monte Carlo and multiscale modeling of the complete dissolution process. Close cooperation with experimental colleagues and other simulation groups in the Cluster is expected.

More information about this project is available.
Master's positions are available for the following projects:
SIMULATION OF SUPERSPREADERS AT AIR/WATER AND POLYMER/WATER INTERFACES
A central problem in the research on superspreading is that experiments cannot observe the molecular-scale behavior of the surfactants. In this project, you will study the unique physical properties and behavior of trisiloxane surfactants at interfaces using Molecular Dynamics (MD) simulations, a simulation method of steadily increasing importance in academia and industry. Your work will include various aspects of MD, including preparation of the simulations, their execution on high performance computers, and their analysis.

More information about this project is available.
ADVANCED METHODS FOR LONG-RANGED DISPERSION SOLVERS
This project will investigate methods for improving the efficiency of simulations which require the use of long-ranged solvers for dispersion interactions, such as interfacial simulations relying on Lennard-Jones potentials. Possible approaches include porting the code to accommodate GPU accelerators, as well as developing error estimates for the solver.

More information about this project is available.
ATOMISTIC STUDY OF THE MECHANICAL PROPERTIES OF POLYMER SOLIDS AND MELTS
In many practical engineering problems involving polymers, one is especially interested in their mechanical performance, which differs substantially from that of other materials like metals, ceramics or glasses. Using molecular simulations, it is possible to impose arbitrary deformations onto small samples of the material and to observe the resulting stress response. By doing so, one can capture the entirety of the polymer’s stress-strain relationship. The main goal will be to capture this functional dependence. Since, in general, this dependence will be time dependent, this constitutes a description of a viscoelastic material.

More information about this project is available.
TEMPORAL COARSE-GRAINING STRATEGIES FOR BIOLOGICAL MOLECULES
Existing molecular simulation methods are unsatisfactory for studying many biomolecular problems, particularly because of the slow time scales involved in classical MD simulations. For instance, diffusion processes in polymers or the mechanical and chemical dissolution of lignocellulosic materials occur over timescales of milliseconds and longer. The current limitation of performing MD calculations with femtosecond timesteps therefore represents aa critical barrier. At the same time, there are natural frequencies associated with characteristic molecular motions which can be exploited. Using formal mathematical tools such as spectral decomposition and wavelet analysis, we will develop appropriate time propagators for long-timescale simulations.
MULTIPHASE CATALYSIS in IONIC LIQUID-ORGANIC SOLVENT INTERFACES
(with Prof. Dr. Jürgen Klankermayer, ITMC)

Next-generation chemical processes will require a sustainable separation of reaction products from the reaction medium. In this respect, the application of multiphase systems represents an innovative approach, especially when ionic liquids for the transformation of highly polar bio-renewables are incorporated. Selective modifications of the ligand structure incorporated in the organometallic catalyst, enable us to control the diffusivity of the catalyst within the organic and ionic liquid phases, and additionally allow control of the catalyst location in the interphase.

More information about this project is available (PDF).
MOLECULAR DYNAMICS SIMULATIONS OF INTERFACES
In order to describe an extraction process, interfacial phenomena and their mechanisms have to be considered in detail. Mass transfer rates, orientation effects, surface tension, and capillary waves are good examples of phenomena that influence the characteristics of the liquid-liquid interface and the extraction process as a whole. Moreover, since the presence of impurities in industrial processes also influences the behavior of interphase regions, understanding their role is important as well. In order to investigate these phenomena on a molecular level, two-phase molecular dynamics simulations will be used. This work will contribute to the better understanding of the behavior of interfaces and their phenomena.

More information about this project is available (PDF).
USING DYNAMIC "GRAY-BOX" OPTIMIZATION TO IMPROVE MOLECULAR FORCE FIELDS
A significant problem in molecular simulation is the need to “harmonize” force fields that have been independently parameterized. Currently, most approaches for harmonization of force fields are ad hoc, and are typically based on the concept of “mixing rules,” which defines the new parameters by averaging existing parameters. Unfortunately, there are additional problems: if the force fields have different functional forms, such as an attempt to combine a Lennard-Jones force field with a Buckingham force field, the computational approach becomes even more complicated, as the fitting process requires that the form of one of the force fields be adapted to the other. Circumventing this process requires an alternative method for selecting the new force field parameters. One possible approach for determining these parameters is to use a dynamic optimization method. Dynamic optimization uses the calculation of thermodynamic parameters which have known comparisons to experimental data to guide the selection of force field parameters “on the fly.” At each stage, the results of the target parameters are compared with the target experimental data, which is in turn used to guide the selection of the parameters to be optimized.
DEVELOPING FRAMEWORK SOFTWARE FOR MOLECULAR SIMULATIONS
One of the major challenges with current efforts in molecular simulations is that the different open-source and proprietary simulation packages and analysis tools each have their own interface and means of interacting with the user. This means that data files and scripts prepared for use in one code cannot easily be shared with users of another code. Current research is underway to develop an application program interface (API) environment which will allow for greater interoperability between software tools. As part of this project, students will work with this API framework to develop "ports" in and out of the framework for one or more popular molecular simulation tools.