faculty

Assistant Professor of Chemistry
PhD., Columbia University, New-York;
Postdoctoral, University of California, Berkeley

Theoretical and Computational Chemistry

Phone: 734 647-4495
E-mail: bdunietz@umich.edu

Dunietz Research Group

The understanding of complex systems gained by experimental measurements can be complemented by theoretical models. Computational quantum chemistry (QC) has the ability to provide microscopic insight which is difficult to obtain by other tools. However, the extension of current methodology for such purposes is still far from trivial. Our research aims to further enhance the use of QC methodology for complex systems. New methodological extensions required for the study of systems relevant for material science and biology are devveloped and implemented. Focus is provided to investigate processes involved with excited state dynamics of the extended systems.

The main thrust of the Dunietz research program is to study electron transport through molecular and nano-scale systems, explain relevant experimental observations, and point to schemes to improve the ability to tune their conductances. The core challenge in nanoscience research is the further miniaturization of electronic devices. Molecular-based electronics is an exciting component of these efforts, offering a possible route for achieving the ultimate miniaturization limit and accomplishing the goal of "smart electronics.'' The merit of this field stems from the prospect of fabricating highly efficient electronic devices, in which their functionality is based on the unique properties of single molecules. The increasing interest in this field is reflected by the remarkable strides in the ability to fabricate molecular scale junctions and to measure their conductance properties. Computational modeling of conductance plays a crucial role in this research area, in which insight at the most fundamental level on the electron transport process through the molecular and nano-scale system can be achieved.

In the systems involving electron transport which have been studied by the group, electron transport switching is based on either physical properties or chemical reactivity. The research activity includes both (i) the development of powerful computational tools and (ii) the study of specific molecular and nanoscale systems. The research group develops new approaches for simulating transport under steady-state conditions that effectively treat large molecular models. Additionally, the research develops methods to simulate electron transport under both transient conditions and time-dependent (TD) perturbations. The TD conductance properties of molecular systems will play an important role in the functionality of electronic devices.

The research at our group has been able to achieve progress both in explaining related experiments and in providing predictions and directions for designing the next experiment. This is demonstrated by the selected publications provided below and is further described by the full publications, where other areas of research have been explored. For example, another category of complex systems involve biological relevance. Specifically, we are interested in systems involving processes enabled through electronic excitations and electron transfer.

REPRESENTATIVE PUBLICATIONS

1. Prociuk, A. and Dunietz, B. D., 'Time-dependent current through electronic channel models using a mixed time-frequency solution of the equations of motion', Phys. Rev. B. , Accepted, (2008).
2. Perrine, T. and Dunietz, B. D., 'Conductance of a cobalt(II) terpyridine complex based molecular transistor: A computational analysis', J. Phys. Chem. A., 112, (2008), 2043.
3. Baiz, C. R. and Dunietz, B. D., 'Theoretical studies of conjugation effects on excited state intramolecular hydrogen-atom transfer reactions in model systems', J. Phys. Chem. A., 111, (2007),10139-10143.
4. Perrine, T. and Dunietz, B. D., 'Single molecule field effect transistors: A computational study of the effects of contact geometry and gating field orientation on conductance switching properties', Phys. Rev. B., 75, (2007), 195319.
5. Perrine, T. and Dunietz, B. D., 'Carbonyl mediated conductance through metal bound peptides; a computational study', Nanotechnol 18 (2007), 424003.
6. Chen, Y., Prociuk, A., Perrine, T. and Dunietz, B. D. 'Spin-dependent electronic transport through a porphyrin ring ligating an Fe(II) atom: An ab initio study', Phys. Rev. B.,74, (2006), 245320-9.