# Greater Boston Area Theoretical Chemistry Lecture Series

## 2017-2018 Speaker Schedule

## Reduced Hierarchal Equations of Motion Approach to Multi-dimensional Spectroscopies

### 09/13/17 4:15pm

### MIT Building 4, Room 237

### Yoshitaka Tanimura

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Quantum coherence and its dephasing or relaxation by coupling to an environment plays an important role in nonadiabatic transitions, photoexcitation and tunneling processes. I first introduce a system-bath model to explain how fluctuation and dissipation arises from the environment, and the concept will be illustrated with some examples from chemistry and biology. Then I derive the quantum hierarchal Fokker-Planck equations (QHFPE) on the basis of the Feynman-Vernon influence functional formalism, which can deal with strong system-bath coupling and non-Markovian noise.

By applying hierarchal formalism to multi-electric states, we can investigate laser excitation and photoisomerization process described by multi-electric state numerically rigorously. As an example, we computed Wigner distributions for excited, ground, and coherent states. We then investigated excited state dynamics involving transitions among these states by analyzing electronic spectra with various values of the heat bath parameters. Our results provide predictions for spectroscopic measurements of photoexcitation and photoisomerization dynamics.

** References **

Y. Tanimura, Real-Time and Imaginary-Time Quantum Hierarchal Fokker-Planck Equations, J. Chem. Phys. 142, 144110 (2015).

T. Ikeda and Y. Tanimura, Probing photoisomerization processes by means of multi-dimensional electric spectroscopy: The Multi-state quantum hierarchal Fokker-Planck Equation approach, J. Chem. Phys. 146, 014102 (2017)

## The Dynamics of Coupled Nuclear-Electronic Motion: At the Intersection of Statistical Mechanics, Electronic Structure Theory, and Solid State Physics

### 10/25/17 4:15pm

### MIT Building 4, Room 237

### Joe Subotnik

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In this talk, I will give an overview of the theory of mixed quantum-classical nuclear-electronic motion both in solution and at metal surfaces, focusing on both stochastic and mean-field descriptions. This theory gives a clear and intuitive picture of electronic relaxation in a condensed environment, e.g. how photo-excitation can lead to macroscopic charge transfer and how the second law of thermodynamics (i.e. entropy growth) emerges from microscopically reversible dynamics. I will attempt to give an introductory but also deep account of this rich field of study. Towards the end, I will highlight open questions, especially at metal surfaces, where propagating ab initio calculations remains very daunting.

## TBD

### 02/07/18 4:15pm

### MIT Building 4, Room 237

### Revati Kumar

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** TBD **

## TBD

### 02/14/18 4:15pm

### MIT Building 4, Room 237

### Yuji Sugita

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** TBD **

## TBD

### 02/28/18 4:15pm

### MIT Building 4, Room 237

### Tim Berkelbach

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** TBD **

## TBD

### 03/14/18 4:15pm

### MIT Building 4, Room 237

### Ignacio Franco

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** TBD **

## TBD

### 03/28/18 4:15pm

### MIT Building 4, Room 237

### James Kindt

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** TBD **

## TBD

### 04/11/18 4:15pm

### MIT Building 4, Room 237

### John Stanton

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** TBD **

## TBD

### 05/02/18 4:15pm

### MIT Building 4, Room 237

### Mark Gordon

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** TBD **

## TBD

### 05/16/18 4:15pm

### MIT Building 4, Room 237

### Trygve Helgaker

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** TBD **

#### Past Schedules