Critical Reinvestigation on Vibronic Couplings in Picene from View of Vibronic Coupling Density Analysis

TL;DR

This study evaluates vibronic coupling constants in picene's various states using density functional theory, compares simulated spectra with experiments, and critically analyzes previous findings through vibronic coupling density analysis.

Contribution

It introduces a vibronic coupling density analysis to interpret vibronic couplings and critically reassesses prior reported constants in picene.

Findings

Calculated vibronic coupling constants agree with experimental spectra.

Vibronic coupling density analysis clarifies electronic-vibrational relations.

Previous reported constants are critically evaluated and discussed.

Abstract

Vibronic coupling constants in the monoanionic, trianionic, and excited states of picene are evaluated from the total energy gradients using the density functional theory. Employing the calculated vibronic coupling constants in the excited state of the neutral molecule, electron energy loss spectrum (EELS) is simulated to be compared with the experimental spectrum. The calculated vibronic coupling constants are analyzed in terms of the vibronic coupling density which enables us to analyze vibronic couplings based on the relation between the electronic and vibrational structures. The vibronic coupling constants reported by Kato et al. [J. Chem. Phys. 116, 3420 (2002) and Phys. Rev. Lett. 107, 077001 (2011)] are critically discussed based on the vibronic coupling density analysis.