aspuru-list November 2015

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[Aspuru-Guzik Group List] Group Meeting in 5 minutes

by Doran Bennett

Hi Everyone, This is a reminder that group meeting is in the Division Room in 5 minutes. See you there! Doran

8 years, 6 months

[Aspuru-Guzik Group List] Prineha's Schedule

by Doran Bennett

Hi Everyone, This is the schedule of Prineha's visit tomorrow. Please double check your time. The majority of the meetings with group members will occur at the couches by the excitonics offices, with the exception of the meeting with the quantum computing group. I look forward to seeing you all at Prinha's talk tomorrow! Doran

8 years, 6 months

[Aspuru-Guzik Group List] ITAMP lunch seminar - Yulia Shchadilova , Harvard (11/20)

by Stefan Pabst

8 years, 6 months

[Aspuru-Guzik Group List] Group Meeting, Nov 18, 11 AM, M217

by Ian Kivlichan

Hi all, Tomorrow Jorge will give group meeting. See below for the title and abstract. The meeting will be at the regular 11 AM time, but due to a mix-up from earlier the Div Room isn't free until 11:30... M217 is free (so the meeting will tentatively be there - emailed John to confirm) and I'll email ASAP if anything changes. All the best, Ian ------------------------------------- Speaker: Jorge Aguilera-Iparraguirre Title: The search for efficient OLED emitters Abstract: Follow a molecule in its thrilling journey to become an efficient OLED emitter. Starting with a million of its fellow candidates in a virtual library in the depths of New Siberia. Moving west to Holyoke to be computed with the hundred thousand survivors of the Machine Learning filter ravage. Going even more to the west, to the shores of Taiwan and South Korea, to be synthesized with a few dozens molecules that made it this far. And the final steps, for the lucky few, back to the origin, now to the riverside of the Charles, in "the institute" (for not Fallout 4 fans, MIT), to end up in the final devices to produce world record EQE (or not), and die a few minutes latter.

8 years, 6 months

[Aspuru-Guzik Group List] Visiting Post-doctoral Candidate: Prineha Narang

by Doran Bennett

Hi Everyone, Tomorrow, Thursday Nov. 19, Prineha Narang will be visiting our group. I have already e-mailed out the schedule to those of you who requested a meeting with her. If anyone is not on the schedule but would really like to meet with Prineha, please let me know ASAP. In addition to meeting with group members, Prineha will also be giving group meeting - her abstract is below - in the Division room from 2:30-4:00pm as shown on our group calendar. If you have time, please plan on attending even if the work is a bit far afield from your usual area of expertise. All the best, Doran Bennett

8 years, 6 months

[Aspuru-Guzik Group List] Theochem Conference - TODAY MIT 4-163 4:00PM

by Romero Fontalvo, Jhonathan

The theochem talk will be today at 4:00PM in MIT 4-163. Prof. Kronik will be talking about density functional theory applied to spectroscopy. Best, Jhonathan. *Theoretical spectroscopy using density functional theory: new ideas for long-standing problems* Leeor Kronik Weizmann Institute of Science, Rehovoth 76100, Israel Department of Materials and Interfaces, E-mail: leeor.kronik(a)weizmann.ac.il *Abstract* Accurate prediction of the electronic structure and optical properties is essential for rational design of materials for novel (opto)electronic applications. Quantities of interest include, e.g., the bandgap, band dispersion and band width, optical absorption, exciton binding energies, and more. Preferably, we would like to predict such quantities using density functional theory (DFT), because the relative computational simplicity afforded by DFT allows us to attack realistic problems. Unfortunately, despite many other successes, DFT has traditionally struggled with prediction of the above quantities. Specifically, research has been fraught with very difficult questions as to the extent to which spectroscopic conclusions can be drawn from DFT even in principle, followed by serious concerns as to the reliability of typical DFT approximations in practice. In this lecture, I will start with a tutorial overview on DFT. I will then focus on new formal and practical approaches which offer fresh answers to the above long-standing questions. In particular, I will show that DFT can, in many cases, mimic successfully the quasi-particle picture of many-body theory, allowing for quantitative calculations of both single- and two-particle excitations. I will show how this is achieved for finite systems, present initial generalizations to solids, and discuss limitations and remaining challenges. -- Jonathan Romero Fontalvo *Ph.D. Student in Chemical Physics* *Harvard University* Website: https://sites.google.com/site/jonathanromeroswebsite/

8 years, 6 months

[Aspuru-Guzik Group List] Fwd: Latest work with molecular data on the web

by Alan Aspuru-Guzik

Dear all, This is what our friend and colleague Marcus Hanwell has been up to at Kitware. It is open source and I hope could benefit us a bit aswell. Check out his email Alan Alán Aspuru-Guzik | Professor of Chemistry and Chemical Biology Harvard University | 12 Oxford Street, Room M113 | Cambridge, MA 02138 (617)-384-8188 | http://aspuru.chem.harvard.edu | http://about.me/aspuru ---------- Forwarded message ---------- From: Marcus D. Hanwell <marcus.hanwell(a)kitware.com> Date: Tue, Nov 17, 2015 at 12:55 PM Subject: Latest work with molecular data on the web To: Alan Aspuru-Guzik <alan(a)aspuru.com> Hi Alan, It was great to see you at the ACS, shame we didn't get together socially but I can appreciate how busy you are. I wanted to let you take a look at a demo of something we developed as part of a Phase I SBIR, and I think it really speaks to some elements of what we proposed, https://openchemistry.kitware.com/ This is a Python-based server, exposing data, authentication, etc as RESTful endpoints returning JSON predominantly. It uses 3DMol to render molecules using WebGL on the client side, and Avogadro libraries on the backend to generate/cache cube files. The isosurface and vibration frames are all generated client side. This is based on AngularJS on the frontend to coordinate a single page web application that can make asynchronous calls for data. It is still a little rough, but hopefully it gives you a flavor of the technical direction I am working in. The RESTful API is documented, and can be tested from, https://openchemistry.kitware.com/api/v1 I wonder if any of this pairs with what you are working on, and would really appreciate a support letter if it does. I would be happy to share the final report with you if you are interested. I would still love to find a funding opportunity so that we might push this further, hopefully the work we have done here can make a resubmission more compelling to the DOE now we have some more compelling demos to show off some of the client-server work. Best wishes, Marcus -- Marcus D. Hanwell, Ph.D. Technical Leader, Kitware Inc. (518) 881-4937

8 years, 6 months

[Aspuru-Guzik Group List] Excitonics Seminar TODAY - 4:30 - RM 36-428 - CARLOS SILVA

by Catherine M Bourgeois

SEMINAR TODAY AT 4:30 TODAY Please post and forward to your groups CENTER FOR EXCITONICS SEMINAR SERIES Are excitation spectral lineshapes in semicrystalline polymeric semiconductors dominated by two-dimensional excitonic coupling or chromophore energetic disorder? November 17, 2015 at 4:30pm/ 36-428 Carlos Silva Department of Physics/ University of Montreal [CSilva] The optical properties of semicrystalline polymeric semiconductors are governed fundamentally by the interplay of electronic interactions occurring within a given polymer chain and those occurring between chains that constitute crystalline motifs. The competition between through-bond (intrachain) and through-space (interchain) electronic coupling determines two-dimensional spatial coherence of excitons. The balance of intra- and interchain excitonic coupling depends very sensitively on solid-state microstructure of the polymer film (e.g. polycrystalline, semicrystalline with amorphous domains, etc.). Regioregular poly(3-hexylthiophene) (P3HT) has emerged as a model material to study the dependence of excitonic properties on microstructure because its photoluminescence (PL) spectral lineshape reveals intricate information on the magnitude of excitonic coupling, the extent of energetic disorder, and on the extent to which the disordered energy landscape is correlated. Single-chain spectroscopic measurements at low temperature, however, have suggested that spectral lineshapes in the solid state may not be due to photophysical aggregate effects, but rather a manifestation of a large inhomogeneous distribution of emitter energies that is determined by chain conformation. In this presentation, I discuss implementation of coherent two-dimensional PL excitation spectroscopy in order to address this issue. This is an ultrafast probe belonging to the family of 2D optical spectroscopies that allows measurement of correlations between quantum transitions induced by the electromagnetic field in the excitation spectrum, detected via the time- and spectrally-integrated PL intensity. Using this technique, we identify cross peaks between 0-0 and 0-1 excitation peaks, and we measure their time evolution, which we interpret within the context of a hybrid HJ aggregate model. By measurement of the homogeneous linewidth in diverse polymer microstructures, we address the nature of optical transitions within such hybrid aggregate model. These dynamics depend strongly on sample processing, and we discuss the relationship between microstructure, steady-state absorption and PL spectral lineshape, and 2D coherent PL excitation spectral lineshape. Carlos Silva is a Professor of Physics and the Canada Research Chair in Organic Semiconductor Materials at the University of Montreal. He is the 2010 laureate of the Herzberg Medal of the Canadian Association of Physicists and has extensive expertise in ultrafast optical probes of electronic dynamics in organic semiconductors with applications in optoelectronics. He obtained a PhD in chemical physics from the University of Minnesota in 1998 and was a Postdoctoral Research Associate in the Cavendish Laboratory at the University of Cambridge from 1998 to 2001. In 2001 while at Cavendish, received an Advanced Research Fellowship from the UK Engineering and Physical Sciences Research Council. The central theme of his research concerns the understanding of electronic dynamics in organic semiconductors using transient photoluminescence and absorption spectroscopies. The Center For Excitonics Is An Energy Frontier Research Center Funded By The U.S. Department Of Energy, Office Of Science And Office Of Basic Energy Sciences

8 years, 6 months

[Aspuru-Guzik Group List] Group TGIF this Friday

by Sam Blau

Hey everyone, Just wanted to let you know that our group will be hosting TGIF this Friday in the department center. We are hoping to have hard root beer and vanilla ice cream to make floats with, but it's still in the works. If we can't, we're probably leaning towards doing pizza for food instead of the usual peapod snacks, but if you have a strong opinion on the matter let me know since it's flexible. Hope to see you all there! Sam

8 years, 6 months

[Aspuru-Guzik Group List] [qip] David Gosset (Caltech) is visiting us

by Cyril Stark

Hi Everybody, David Gosset (Caltech) is visiting us this week from Wednesday afternoon until Friday. He is going to give the Friday seminar (see below). Please let me know if you would like to meet David. Best, cyril -- Title: Some consequences of frustration-freeness Place: 6C-442 Time: 1:30 (Nov 20) Abstract: Frustration-free local Hamiltonians are a commonly studied subclass of (general) local Hamiltonians. A frustration-free local Hamiltonian H can be written as a sum of terms, such that any ground state of H also has minimal energy for each term. In this talk I will describe some fundamental consequences of frustration-freeness. Firstly I will consider the scaling of the correlation length with spectral gap. Hastings proved that a ground state of a local Hamiltonian with spectral gap g has correlation length upper bounded as O(1/g). This bound cannot be improved in general. However, frustration-free systems satisfy a stronger O(1/sqrt(g)) upper bound on correlation length. Secondly I will consider the scaling of the spectral gap with system size. For 1D translation-invariant frustration-free systems which are gapless in the thermodynamic limit, the spectral gap of an open boundary chain of size n is upper bounded inverse quadratically with n. In contrast if we remove the frustration-freeness restriction then the gap can scale inverse linearly with system size. Finally, I will briefly discuss an open question concerning the scaling of entanglement entropy with spectral gap in frustration-free systems. This talk is based on a joint work with Yichen Huang (arxiv:1509.06360) and a joint work with Evgeny Mozgunov (to appear on arxiv soon). -- Cyril Stark Center for Theoretical Physics Massachusetts Institute of Technology 77 Massachusetts Ave, 6-304 Cambridge, MA 02139, USA _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

8 years, 6 months

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aspuru-list November 2015