Dresden 2020 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 26: Frontiers in Electronic-Structure Theory - Focus on Electron-Phonon Interactions II (joint session O/CPP/DS/HL)

CPP 26.3: Talk

Monday, March 16, 2020, 15:30–15:45, GER 38

Ab Initio Linear and Pump-Probe Spectroscopy of Naphthalene Crystals — •Alan Lewis¹ and Tim Berkelbach^2,3 — ¹MPSD, Hamburg, Germany — ²Columbia University, New York City, USA — ³Flatiron Institute, New York City, USA

Linear and non-linear spectroscopies are powerful tools used to investigate the energetics and dynamics of electronic excited states of both molecules and crystals. While highly accurate ab initio calculations of molecular spectra can be performed relatively routinely, extending these calculations to periodic systems is challenging. Here, we present calculations of the linear absorption spectrum and pump-probe two-photon photoemission spectra of the naphthalene crystal using equation-of-motion coupled-cluster theory with single and double excitations (EOM-CCSD). Molecular acene crystals are of interest due to the low-energy multi-exciton singlet states they exhibit, which have been studied extensively as intermediates involved in singlet fission. Our linear absorption spectrum is in good agreement with experiment, predicting a first exciton absorption peak at 4.4 eV, and our two-photon photoemission spectra capture the behavior of multi-exciton states, whose double-excitation character cannot be captured by current methods. The simulated pump-probe spectra provide support for existing interpretations of two-photon photoemission in closely-related acene crystals such as pentacene.