Dic. 13, 2018. For many years we have been dreaming about the concept of “Laser-dressed materials” in which light is used to reversibly distort the electronic structure of matter and impart new properties. Bing’s paper “Optical absorption properties of laser-driven matter” summarizes our progress on this beautiful but very challenging topic. In it, we develop a theory for the optical absorption of electronic materials driven far from equilibrium by resonant and nonresonant lasers. Using the theory we show that non-resonant light can be used to reversibly transform a transparent semiconductor into a broadband absorber and open strong absorption and stimulated emission bands at very low frequencies (meV). These developments offer a platform to understand and predict the emergent optical properties of materials dressed by the electric field of light. Check it out here!
Nov 7, 2018. Bing’s paper “Electronic interactions do not affect electronic decoherence in the pure-dephasing limit” has now been published in J. Chem. Phys. In it, we show that in the pure dephasing limit changing the degree of electronic correlation in molecules does not affect the electronic decoherence because the effect of varying the electronic interactions is to simply rigidly shift in energy the diabatic potential energy surfaces without changing their shape; thus keeping the nuclear dynamics in these surfaces that leads to the electronic decoherence intact. The larger implication of this result is that the exact electronic decoherence with full electronic correlation (which is numerically very challenging to obtain) is equivalent to that obtained from a lower-level electronic structure theory such as Hartree-Fock (which is numerically feasible) provided that the dynamics is pure dephasing with and without the electronic correlation. As such, the analysis opens opportunities to study exact electronic decoherence with approximate electronic structure theories. Check it out here!
Oct. 17, 2018. Leopoldo is awarded a Weissberger Memorial Fellowship for the 2018-19 academic year. Congratulations!
Oct. 14, 2018. Group lunch and farewell party for our own Bing Gu who is now heading to Irvine/LA. Pumpkin carving action for the occasion.
Oct. 11, 2018. Ignacio is at UMichigan giving a P. Chem. talk on decoherence in molecular processes. Thanks EG for the invite and discussions!
Sept 24, 2018. Antonio’s paper “Stark control of electrons across interfaces” has now been published as a rapid communication in Phys. Rev. B! In it, we introduce a scenario for the laser control of electron dynamics across interfaces based on opening quantum tunneling channels for interfacial charge transport using the Stark effect induced by strong few cycle laser pulses. The scenario is used to develop a scheme to transiently turn an insulating semiconductor heterojunction into a conductor on a femtosecond timescale! Check it out here (link).
Sep. 3, 2018. Antonio is in Cartagena presenting his work on “Stark Control of Electrons at Interfaces” in the 10th Photodynamics meeting that is happening in Cartagena.
Aug. 6-10, 2018. Leopoldo and Ignacio are at the GRC on Donor-Acceptor Interactions in Newport, RI. Here is Leopoldo discussing the integration of mechanochemistry with molecular conductance with Mark Ratner.
July 27, 2018. Leopoldo passed his qualifying exam, and is now officially a Ph.D. candidate in Chemistry. Congrats!
July 25, 2018. Wen just gave his 3rd year presentation, and is now a Ph.D. candidate in the material science program. Congrats Wen!
July 24, 2018. The theory-experiment collaborative paper with M. Koch (FHI), L. Grill (Graz) and others investigating the electrical and mechanical properties of single graphene nanoribbons is now out in Phys. Rev. Lett! Zhi played a major role in this work by providing atomistic understanding into the experimental observations. Congrats Zhi! Check it out here. See also a synopsis here.
June 26-30, 2018. The Telluride workshop that we have been organizing with Joel Yuen-Zhou on “Quantum Frontiers in Molecular Science” is now happening! Lots of great science!
June 19, 2018. Participants of the Summer Fellowship Program for International Students that Ignacio coordinates. Bottom row: Suhyeon Kim (Korea), Gabriel Martínez (Colombia), Aleksa Milosavljević (Serbia), Diego Garay (Spain), Maria Camila Aguilera (Colombia) and Karla Sánchez (Mexico).
June 18, 2018. Antonio Garzón just presented his 3rd year talk on “Stark Control of Electrons at Interfaces”. Good stuff Antonio!
May 29, 2018. Diego Garay from the University of Barcelona joins the group for the summer as part of our prestigious summer research fellowship program for international students. Welcome Diego!
May 25, 2018. Liping’s paper “Stark control of electrons along nanojunctions” just appeared in Nature Communications! Strong non-resonant few-cycle laser pulses can be used to induce ultrafast phase-controllable currents along nanojunctions but the microscopic origin is unclear. Here, we present time-dependent quantum transport simulations that recover the experimental observations and offer a simple intuitive picture of the effect. The paper summarizes many years of simulation work by Liping. Check it out (link) (pdf)
May 22, 2018 Bing received the 2018 PHYS Young Investigator Award of ACS due to his work on quantum dynamics, quantum decoherence and non-equilibrium properties of matter. In Rochester he has (i) developed a trajectory-based method for large-scale non-adiabatic dynamics, (ii) constructed a general expression for purity dynamics and applied it to electronic decoherence problems, and (iii) developed a theory for optical absorption properties of laser-dressed materials. Bing will present the work on electronic decoherence in the upcoming ACS national conference in Boston! Well deserved Bing! Check it out here: http://phys-acs.org/postdocs/2018.html.
May 19, 2018. Leopoldo has completed all of the requirements for his master’s degrees and was awarded his diploma. Well done!
May 16, 2018. Ignacio is at Seattle visiting U. Washington and giving a P. Chem. talk. Thanks DM and XL for the invite and discussions!
May 15, 2018. Ignacio is at UC Irvine giving a P. Chem talk. So many theoreticians to talk to! Thanks CM for this opportunity.
April 30, 2018. Ignacio is very excited to be at Princeton giving a P. Chem. talk. Thanks HR for this invitation!
April 26, 2018. Ignacio is visiting Prof. Matt Reuter at Stony Brook and giving a talk in the highly interdisciplinary Institute for Advanced Computational Science.
April 24, 2018. Ignacio is visiting Yale and giving a P Chem. talk. Such a rich scientific history! Thanks VB for this invite.
April 16, 2018. Ignacio is giving a P Chem. talk at U Oregon. Wonderful discussions in such a beautiful corner of the world. Thanks JC for this very nice invitation!
April 3, 2018. Wen’s paper “Lessons on electronic decoherence in molecules from exact modeling” has now been published in the Journal of Chemical Physics. In it we present computations of the electronic decoherence dynamics using an exact method in which both electronic and nuclear degrees of freedom are taken into account explicitly and fully quantum mechanically. Using them we addresss a series of fundamental questions about electronic decoherence including the effect of changing the mass, the initial state and the strength of the electron-electron interactions. Thanks Wen for teaching us so much about electronic decoherence! Check it out here (link).
April 3, 2018. Ignacio is giving a talk in the James Frank Institute at the University of Chicago. Excited to be in a place that cares so much about laser control! Thank you T&S!
March 27, 2018. Ignacio is super excited to be back at the University of Toronto to give a talk in the P. Chem. seminar series in which he was trained. Thanks Michael K.!
March 13-15, 2018. Ignacio is in Boston visiting BU, MIT and HU and giving a talk in the Greater Boston Area Theoretical Chemistry Lecture Series on “Understanding electronic decoherence in molecules” and on the “Stark control of electrons”. Thanks J&B for this very nice invitation!
March 2, 2018. Ignacio is visiting Duke, giving a P. Chem. talk and learning many things about electron transfer, DFT, glasses, and beyond. Thank you David B. for this wonderful invitation!
February 27, 2018. Ignacio is in NYU giving a P. Chem. talk. Thank you Mark for this wonderful opportunity!
February 15, 2018. Ignacio is at Cornell visiting fellow theoreticians in the Finger Lakes and giving a P. Chem. talk. Thanks Nandini and Rob for this very nice invitation!
February 13, 2018. Zhi’s paper “Modeling Non-Reactive Molecule-Surface Systems on Experimentally Relevant Time and Length Scales: Dynamics and Conductance of Polyfluorene on Au(111)” has now been accepted to J. Phys. Chem. Lett. In it we develop a very accurate force-field for non-reactive metal-molecule interactions and use it to model the challenging experiment by Leonhard Grill pulling polyfluorene adsorbed on gold. It constitutes a very deliberate effort to bring theory closer to experiments in this class of molecular electronics experiments. Check it out here!
February 8, 2018. After many years, Ignacio is back in Evanston to give a theory talk in the Chemistry Department. He was very very excited to be back in the 4th floor of the Nano building. Thanks George and Mark for making this happen!
February 7, 2018. Ignacio is in Urbana Champaign giving a P. Chem. talk at the University of Illinois. Thanks Nancy and Josh for a wonderful day of Science!
January 25, 2018. Leopoldo’s paper “Signatures of Conformational Dynamics and Electrode-Molecule Interactions in the Conductance Profile During Pulling of Single-Molecule Junctions” was just accepted to J. Phys. Chem. Lett. There, we demonstrate that conductance can act as a sensitive probe of conformational dynamics and electrode-molecule interactions during the equilibrium and non-equilibrium pulling of molecular junctions, offering an efficient solution to experimentally monitor conformational dynamics at the single-molecule limit. Check it out here!
January 23, 2018. Ignacio is in San Diego giving a P. Chem. talk at the University of California, San Diego. Thanks Joel, Misha and Francesco for the wonderful invitation!
January 18, 2018. Ignacio is in Philadelphia giving a P. Chem. talk at the University of Pennsylvania. Thanks Joe S. for putting together a great day of science!
January 17, 2018. Bing’s paper generalizing the theory for the electronic decoherence timescale was just accepted to J. Phys. Chem. Lett. The theory offer a rigorous understanding of early time electronic decoherence processes that accompany basic molecular events, and demonstrate that electronic transitions among diabatic states play a major role in the decoherence dynamics. Check it out here!
November 6, 2017. Ignacio is at Los Angeles giving a talk in the P. Chem. Seminar of USC. Thanks Oleg and Anna for the wonderful invitation!
November 2, 2017. Ignacio is at the CUNY Graduate Center in NYC giving a talk in the workshop “Quantum conductance and forces across molecular junctions” organized by Seogjoo Jang. Thanks Suggy for putting such a wonderful workshop together!
October 20, 2017. Bing received a travel award from the division of chemical physics to attend the APS March meeting in Los Angeles!
October 16, 2017. Ignacio is in Erlangen visiting the group of Peter H. at the Friedrich-Alexander University and giving a talk on “Laser control of electrons”. Thanks Peter, Tak and Christian for the hospitality!
October 9-13, 2017. Ignacio is in Bremen talking about laser-dressed materials and other deeply optoelectronic processes in the CECAM meeting “Charge carrier dynamics in nanostructures: optoelectronic and photo-stimulated processes”. What a terrific meeting!
September 25-29, 2017. Ignacio is in Cuernavaca, Mexico presenting the work of the group on electromechanical processes in junctions in the conference “Transport at the Nanoscale” at the Centro Internacional de Ciencias. Thanks Thomas Stegmann and Carmen Herrmann for the wonderful invitation!
August 28, 2017. Bing’s general but simple formula for decoherence times is now out in the Journal of Physical Chemistry Letters! As it turns out, the initial purity decay is Gaussian and the associated timescale is determined by initial-time fluctuations. From this general formula it follows that mixed quantum-classical methods like Ehrenfest dynamics can capture decoherence correctly provided the initial conditions are sampled from a Wigner distribution. Check it out: link
August 6-11, 2017. Bing, Wen, Antonio and Ignacio are in Hadley, MA attending the GRC on Quantum Control of Light Matter and presenting posters. One of the contributions of the group ¨Quantifying early-time decoherence dynamics through fluctuations¨ was upgraded to a hot topic talk!
July 17-20, 2017. Ignacio is in Telluride attending the workshop on ¨Nonequilibrium Phenomena,Nonadiabatic Dynamics and Spectroscopy¨ and presenting the work on the group on modeling of electromechanical spectroscopies in molecular junctions.
June 19, 2017. Pawel Wójcik from the University of Warsaw joins the group for the summer as part of our prestigious summer research fellowship program for international students. Pawel will be working on the absorption properties of laser-dressed materials. Welcome Pawel!
July 1, 2013. Dr. Liping Chen joins the lab. Liping brings with her a tremendous amount of experience and expertise in electronic structure and quantum dynamics. Welcome Liping!
June 23, 2013. We are finally in Rochester!