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Poster Session

Poster Session I (4pm-6pm CDT)

4:00 pm – 6:00 pm, Tuesday June 4 Session D00
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Ultrafast nonadiabatic relaxation of photoexcited C60: Optimizing computational accuracy vis-à-vis expense

Poster 41
Presenter: Matthew Wholey (Northwest Missouri State University)
Authors: Joan Jimenez (Northwest Missouri State University), Ruma De (Northwest Missouri State University), Mohamed Madjet (Northwest Missouri State University), Himadri Chakraborty (Northwest Missouri State University)

Relaxation dynamics of photoexcited electrons in fullerene materials underlies applications in fields, namely, organic photovoltaics and medical photothermal therapy. In this work, we use a computational approach of electron-phonon coupled nonadiabatic molecular dynamics (NAMD) based on density functional theory [1,2] to simulate such relaxation process in C60 molecule. The methodology relies on a combination of the fewest-switches surface hopping approach and Kohn−Sham single-particle description. We calculate the femtosecond evolution of the population of initial excited states and of various intermediate states up to the band edge. Effects of excited state energy gaps and nonadiabatic couplings are studied. Two NAMD workflow tracks are adopted using, (i) QMflows-namd module [3,4] and (ii) Libra module [5], and the results are compared. The primary focus, as part of our ongoing campaign, has been to optimize the workflow to produce acceptably high accuracy results using less expensive exchange-correlation functionals.

[1] M.E. Madjet et al, Phys. Rev. Lett. 126, 183002, (2021).

[2] M. Madjet et al. J. Phys. Chem. Lett 8, 18 (2017).

[3] F. Zapata et al, J. Chem. Inf. Model. 59, 3191 (2019).

[4] E. Ali et al; https://arxiv.org/abs/2306.16386.

[5] M. Shakiba et al, Software Impacts 14 100445 (2022).

Funding acknowledgement

National Science Foundation Grant No. PHY-2110318. BARTIK High-Performance Cluster at Northwest Missouri State University (National Science Foundation Grant No. CNS-1624416). Services provided by the PATh Facility [1,2,3,4], which is supported by the National Science Foundation Award No. 1836650:[1] Pordes, R. et al,  (2007). The open science grid. J. Phys. Conf. Ser., 78, 012057. https://doi.org/10.1088/1742-6596/78/1/012057.[2] Sfiligoi, I. et al, (2009). The pilot way to grid resources using glideinWMS. 2009 WRI World Congress on Computer Science and Information Engineering, 2, 428–432. https://doi.org/10.1109/CSIE.2009.950.[3] OSG. (2015). Open Science Data Federation. OSG. https://doi.org/10.21231/0KVZ-VE57.[4] PATh Facility. (2022). https://doi.org/10.21231/k4r7-s230.

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