[MOS] CANCELLED: 3/13 - Modern Optics and Spectroscopy Seminar with Andrew H. Marcus, University of Oregon

[Christine Brooks]

In anticipation of tomorrow’s snowstorm, this seminar has been cancelled.

Christine Brooks
Administrative Assistant
Massachusetts Institute of Technology
Department of Chemistry
77 Massachusetts Ave, 6-333
Cambridge, MA 02139
p: 617.253.7239
e: cbrooks at mit.edu<mailto:cbrooks at mit.edu>


From: Christine Brooks <cbrooks at mit.edu>
Date: Thursday, March 8, 2018 at 12:13 PM
To: mos <mos at mit.edu>
Subject: 3/13 - Modern Optics and Spectroscopy Seminar with Andrew H. Marcus, University of Oregon

There will be a Modern Optics and Spectroscopy Seminar held next Tuesday, March 13 at 12pm in NE47-189

**Please note location**

Andrew H. Marcus
University of Oregon

“Spectroscopic studies of exciton-coupled cyanine dimers (Cy3)2 in double-stranded DNA”

Understanding the properties of electronically interacting molecular chromophores,
which involve internally coupled electronic-vibrational motions, is important to the spectroscopy
of many biologically relevant systems. We apply linear absorption, circular dichroism (CD),
and two-dimensional fluorescence spectroscopy (2DFS) to study the polarized collective
excitations of excitonically coupled cyanine dimers (Cy3)2 that are rigidly positioned within the
opposing sugar-phosphate backbones of the double-stranded region of a double-stranded (ss) –
single-stranded (ss) DNA fork construct. We show that the exciton-coupling strength of the
(Cy3)2-DNA construct can be systematically varied with temperature below the ds – ss DNA
denaturation transition. We interpret spectroscopic measurements in terms of the Holstein
vibronic dimer model, from which we obtain information about the local conformation of the
(Cy3)2 dimer, as well as the degree of static disorder experienced by the Cy3 monomer and the
(Cy3)2 dimer probe locally within their respective DNA duplex environments. The properties of
the (Cy3)2-DNA construct we determine suggest that it may be employed as a useful model
system to test fundamental concepts of protein-DNA interactions, and the role of electronic-vibrational
coherence in electronic energy migration within exciton-coupled bio-molecular
arrays.



Refreshments will be served immediately following the seminar


Christine Brooks
Administrative Assistant
Massachusetts Institute of Technology
Department of Chemistry
77 Massachusetts Ave, 6-333
Cambridge, MA 02139
p: 617.253.7239
e: cbrooks at mit.edu<mailto:cbrooks at mit.edu>

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