Qixi Mi

Northwestern University
2190 Campus Drive
Ryan Hall
1030
Evanston, IL 60208-3113

E-mail: q-mi@northwestern.edu

Ph: (847)467-6696

Education

1999 – 2003
B. S. with honors, Peking University, Beijing, China
Major in chemistry, minor in computer
2003 – 2008 (expected)
Ph. D., Northwestern University, Evanston, IL
Physical/theoretical division, Department of Chemistry

Advisors: M. R. Wasielewski, M. A. Ratner

Teaching

General chemistry laboratory (freshman level)
Quantum mechanics and spectroscopy (junior/senior level)
Quantum chemistry (graduate level)

Honors and Memberships:

American Chemistry Society, since 2007
Northwestern CSSA Membership Award, 2006
Phi Lambda Upsilon, 2005

Publications:

(1) Mi, Q.; Wasielewski, M. R.; Ratner, M. A., Accurate and general solutions to three-dimensional anisotropies: Applications involving dipole-dipole, spin-orbit interactions and liquid crystals. 2009, in revision.

(2) Giacobbe, E. M.; Mi, Q.; Colvin, M. T.; Cohen, B.; Ramanan, C.; Scott, A. M.; Marks, T. J.; Ratner, M. A.; Wasielewski, M. R., Ultrafast intersystem crossing and spin dy-namics of photoexcited perylene-3,4:9,10-bis(dicarboximide) covalently linked to nitroxide radicals at fixed distances. 2008, in preparation.

(3) Mi, Q.; Weiss, E. A.; Ratner, M. A.; Wasielewski, M. R., Influence of structural dynamics on charge recombination rates in photogenerated radical ion pairs: evidence from EPR spectroscopy and computation. Appl. Magn. Res. 2007, 31, 253-270.

(4) Chernick, E. T.; Mi, Q.; Vega, A. M.; Lockard, J. V.; Ratner, M. A.; Wasielewski, M. R., Controlling electron transfer dynamics in donor-bridge-acceptor molecules by increas-ing unpaired spin density on the bridge. J. Phys. Chem. B 2007, in press.

(5) Mi, Q.; Chernick, E. T.; McCamant, D. W.; Weiss, E. A.; Ratner, M. A.; Wasielewski, M. R., Spin dynamics of photogenerated triradicals in fixed distance electron donor-chromophore-acceptor-TEMPO molecules. J.
Phys. Chem. A 2006, 110, 7323-7333.

(6) Dance, Z. E. X.; Mi, Q.; McCamant, D. W.; Ahrens, M. J.; Ratner, M. A.; Wasielewski, M. R., Time-resolved EPR studies of photogenerated radical ion pairs separated by p-phenylene oligomers and of triplet states resulting from charge recombination. J. Phys. Chem. B 2006, 110, 25163-25173.

(7) Chernick, E. T.; Mi, Q.; Kelley, R. F.; Weiss, E. A.; Jones, B. A.; Marks, T. J.; Ratner, M. A.; Wasielewski, M. R., Electron donor-bridge-acceptor molecules with bridging nitronyl nitroxide radicals: Influence of a third spin on charge- and spin-transfer dynamics. J. Am. Chem. Soc. 2006, 128, 4356-4364.

 

My current research joint with Profs. Wasielewski and Ratner includes characterization and manipulation of the time evolution of molecular systems featuring 2 or 3 unpaired while entangled electron spins. These intriguing systems are generated in an initial pure spin state by photoexcitation and subsequent ultrafast charge separation (CS) within a series of donor-acceptor (D-A) or donor-acceptor-radical (D-A-R) arrays, which then develops into a final state, with spin information delivered by the moving electron during charge recombination (CR). Various time-resolved EPR (Electron Paramagnetic Resonance) techniques, utilizing continuous-wave (CW) m.w. fields and pulse sequences, are employed to probe and/or maneuver the spin dynamics of the systems. The resulting spectra and kinetic traces are further analyzed by theoretical modeling and computer simulations to reveal the convoluted information of the systems, such as the spin-spin exchange coupling constants, which, ranging from 0.1 to 10−8 eV, switch on or off the synchronization between the individual spin precession. This study is fundamental in the emerging area of spintronics and is promising for physical implementation of quantum logics at scalable level and benign conditions.

 

 

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