Greater Boston Area Theoretical Chemistry Lecture Series

2014-2015 Speaker Schedule

Electronic Dynamics in Complex Environments: From Electron Transfer to Singlet Fission

09/10/14 4:00pm

MIT Building 4, Room 163

Troy Van Voorhis

MIT




Troy Van Voorhis

Some of the most basic chemical reactions are those that involve primarily the motion of electrons with little rearrangement of the nuclei. Prominent examples include electron transport and excitonic energy transfer as well as more exotic phenomena such as singlet fission. These reactions are the centerpiece of artificial photosynthetic complexes, organic PVs and essentially all of redox chemistry. In treating the dynamics of these reactions, it becomes clear that knowledge of the molecular conformation alone is not sufficient to define a reaction coordinate (since the nuclei may not more appreciably during the course of the reaction). In this talk, we will discuss how the "reactant" and "product" states for these types reactions can be clearly defined using the electron density as the fundamental variable. We will illustrate the utility of this approach using two examples: electron transfer in solution the simulation of singlet fission in organic photovoltaics.

Systematic Approach to Density Functional Theory

10/15/14 4:00pm

MIT Building 4, Room 163

Kieron Burke

University of California, Irvine




Kieron Burke

Density functional calculations of electronic structure appeared in about 30,000 papers last year. Claims to its first principles nature are being undermined by the hundreds of different approximations available to users. (see J. Chem. Phys. 136, 150901 (2012).) I will explain what DFT is and why it has become so popular. Then I will show how, in fact, density functional approximations are simply semiclassical approximations to the many-electron problem, and that expansion in powers of hbar leads to the systematic construction of density functional approximations. This has produced acGGA, the most accurate generalized gradient approximation ever for atomic correlation energies (see arXiv:1409.4834).

Electronic structure theory: Beyond the black box

10/29/14 4:00pm

MIT Building 4, Room 163

Toru Shiozaki

Northwestern University




Toru Shiozaki

One of the biggest challenges in quantum chemistry is to accurately simulate the electronic structure of molecules and materials in which electron correlation is beyond the perturbative regime. I will first explain conventional theories, such as multi-configuration methods and density matrix renormalization group (DMRG), with an emphasis on the structure and interpretation of their wave functions. Then I will describe a method recently developed by us, called active space decomposition (ASD), which uses molecular geometries to compress the wave functions. This method not only allows us to simulate multi-configuration wave functions of unprecedented size, but also provides natural links to a few-state model Hamiltonians for excitonic/electronic processes. Finally I will present ASD with multiple active sites using the DMRG algorithm and its application to "chemically" one-dimensional systems.

TBD

02/11/15 4:00pm

MIT Building 4, Room 163

Pablo DeBenedetti

Princeton University




Pablo DeBenedetti

TBD

02/25/15 4:00pm

MIT Building 4, Room 163

Peter Wolynes

Rice University




Peter Wolynes

TBD

03/11/15 4:00pm

MIT Building 4, Room 163

Anastasia Alexandrova

UCLA




Anastasia Alexandrova

TBD

03/25/15 4:00pm

MIT Building 4, Room 163

Bill Miller

University of California, Berkeley




Bill Miller

TBD

04/15/15 4:00pm

MIT Building 4, Room 163

Jeremy Smith




Jeremy Smith

TBD

TBD 4:00pm

MIT Building 4, Room 163

Shaul Mukamel

University of California, Irvine




Shaul Mukamel



TBD

TBD

TBD 4:00pm

MIT Building 4, Room 163

Benoit Roux

University of Chicago




Benoit Roux



TBD

TBD

TBD 4:00pm

MIT Building 4, Room 163

Adrian Feiguin

Northeastern University




Adrian Feiguin



TBD

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