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MO: Fachverband Molekülphysik
MO 15: MO Poster 3
MO 15.10: Poster
Mittwoch, 11. März 2020, 17:00–19:00, Empore Lichthof
Investigating the vibronic structure of photosynthetic pigments using screened range-separated hybrid functionals — •Alexander Schubert1,2,3, Yin Song2, Aksu Huseyin3, Jennifer P. Ogilvie2, Eitan Geva2, and Barry D. Dunietz3 — 1Friedrich-Schiller Universität Jena, Germany — 2University of Michigan, Ann Arbor, USA — 3Kent State University, USA
Bacteriochlorophyll a (Bchl a) and chlorophyll a (Chl a) play an important role in the initial charge-separation steps in photosynthetic reaction centers. We investigate the interplay of electronic and vibrational states within the Q-band by means of time-dependent density functional theory (TDDFT) employing a recently developed framework based on a screened range-separated hybrid functional within a polarizable continuum model (SRSH-PCM). Our simulations support the interpretation of polarized two-dimensional electronic spectroscopic measurements. We find that in Bchl a, the Qx and Qy transitions lead to two independent bands with a relative transition dipole angle of 76°, whereas in Chl a, three distinct peaks of different polarizations are obtained which are traced back to a spectral overlap between two electronic transitions and their vibrational replicas[1]. Furthermore, employing the SRSH-PCM scheme to the pseudo-symmetric pigments pairs in bacterial reaction centers reveals that spectral asymmetries may result from locally different effective dielectric environments[2].
[1] Chem.Sci., 10, p.8143 (2019); [2] J.Phys.Chem.B., 123(42), p.8970 (2019).