Controlling non-rigid molecules with plasmon enhanced fields

• Applicant: Dr. Thomas Grohmann
• Subject Area: Theoretical Chemistry: Electronic Structure, Dynamics, Simulation
• Term: from 2014 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 262463525

Alignment and focusing of molecules is a great challenge in molecular sciences, since the outcome - and consequently the success - of many chemical reactions strongly depends on the relative position and orientation of the reaction partners. Here, we suggest a new route for controlling the translational, rotational and torsional motions of polyatomic molecules on the footing of plasmon-enhanced laser fields near the surface of metal nanoparticles. In particular, we wish to achieve alignment and focusing of molecules which show observable torsions in their electronic ground state, i.e. we want to control in addition to their translations and rotations the internal structure of molecules. To this end, we will use the ability of nanoparticles to enhance laser light in order to design strategies to effectively steer molecular motions. Our intentions to address plasmon field controlled molecular motions are manifold. As one application, we wish to control the translational and rotational-torsional dynamics of nuclear spin isomers and enantiomers, respectively. Applying plasmon enhanced fields to control the motions of molecular isomers would be an intriguing extension of preliminary studies as the plasmon enhanced field may open a route to directly decompose a mixture of different nuclear spin isomers or enantiomers into its compounds. Furthermore, we intend to study the influence of decoherence and dephasing on the process of plasmon-enhanced alignment and focusing, not only to understand those mechanisms from a fundamental perspective, but also to develop criteria for the choice of systems and parameters that would allow coherent control in a dissipative environment. Eventually, we attempt to explore how the interaction of the nanoparticle with the molecular species will modify its symmetry properties and, as a consequence, how the dynamics of the molecules will be altered. Combining and extending recent concepts from molecular plasmonics, molecular quantum dynamics of isolated and open quantum systems, quantum chemistry and molecular symmetry, the project we propose here is highly interdisciplinary. We therefore intend not only to establish cross-references between the sub-disciplines but also to demonstrate how combining them can be made prolific for practical applications, ranging from solution chemistry, material research, catalysis or even biology and engineering.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professorin Dr. Tamar Seideman