Electronic excited state of protonated aromatic molecules: protonated Fluorene

TL;DR

This study investigates the excited electronic states of protonated fluorene through spectral analysis and ab-initio calculations, revealing charge transfer characteristics and isomer-specific vibrational progressions.

Contribution

It provides the first detailed spectral and theoretical analysis of protonated fluorene's excited states, highlighting charge transfer effects and isomer distinctions.

Findings

Two vibrational progressions identified, separated by 0.19 eV.

Red shift in spectrum attributed to charge transfer character.

Spectral features linked to different isomers.

Abstract

The photo-fragmentation spectrum of protonated fluorene has been recorded in the visible spectral region, largely red shifted as compared to the first excited state absorption of neutral fluorene. The spectrum shows two different vibrational progressions, separated by 0.19 eV that are assigned to the absorption of two isomers. As in protonated linear PAHs, comparison with ab-initio calculations indicates that the red shift is due to the charge transfer character of the excited state.