MIT Department of Chemistry
Cambridge, MA 02139
mit.edu email: diptarka
Year joined: 2013
|2016||S.B. in Chemistry and Physics||Massachusetts Institute of Technology|
I am working on trying to develop methods for doing exact quantum dynamics of exact, model Hamiltonians in collaboration with Michael Mavros. In particular, I am working on trying to develop an analytic solution to a special case of the Spin-Boson model. I have also worked on generalizations of the Spin-Boson model to study dynamics involving conical intersections.
Thermally Activated Delayed Fluorescence (TADF) of Organic Molecules.
Some organic molecules have a very small energy gap between the first excited singlet and the first excited triplet states, facilitating thermal interconversion between the two. Such molecules are especially attractive for fabrication of energy efficient OLEDs, as they can harvest some of the energy normally wasted in generating non-radiative triplet excitons by indirectly causing such excitons to fluoresce via thermal conversion to singlets (TADF).
The small energy gap is generally a consequence of large CT character of the first excited singlet and triplet states, which reduces the HOMO-LUMO exchange interaction. Excited states with large CT character however, cannot be studied with semi-local TDDFT. Along with Tianyu Zhu and Dave McMahon, I tried to study such states from an ROKS approach in the hope of devising computational protocols that would enable us to predict photophysical properties of CT excited states with just semi-local functionals like B3LYP.
Our work on using ROKS to study TADF materials was published in The Journal of Chemical Theory and Computation.
Large Amplitude Vibrations
Chemical reactions like isomerization and hydrogen transfers often result from Large Amplitude Vibrations. Working in collaboration with Professor Robert Field, I wrote code to solve for very high energy vibrational states of small molecules. We hoped that understanding the character of these high energy states will help us gain further insight into their possible reactions, as well as help assign peaks to the experimental ultrafast spectrum of such processes.