Isolated 2-hydroxypyrene and its dimer: a frequency- and time-resolved spectroscopic study. (19th June 2020)

• Record Type: Journal Article
• Authors: Schmitt, Hans-Christian; Fischer, Ingo; Ji, Lei; Merz, Julia; Marder, Todd B.; Hoche, Joscha; Röhr, Merle I. S.; Mitric, Roland
• Is Part Of: New journal of chemistry. Volume 45:Number 33(2021)
• Page Start: 14949
• Page End: 14956
• Publication Date: 2020-06-19
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/d0nj02391d
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : We investigated isolated 2-hydroxypyrene and its dimer in the gas phase by time- and frequency-resolved photoionisation with picosecond time-resolution. Abstract : We investigated isolated 2-hydroxypyrene and its dimer in the gas phase by time- and frequency-resolved photoionisation with picosecond time-resolution. The experiments are supported by simulations that include an extensive conformational search based on the machine learning ANI-1ccx neural network potential combined with automatic structure classification using a data clustering algorithm. Vibrationally resolved spectra of the S1 ← S0 and S2 ← S0 transitions are reported which are in very good agreement with the simulated spectra at the TDDFT level. As expected from the molecular orbitals involved in the transitions, the red-shifts of the transitions are more pronounced for the S1 state compared to those of unsubstituted pyrene. While a ns-lifetime is observed for the S1 state, the lifetime decreases to 3 ps or less for the origin of the S2 state, indicating a strong interaction between the two states. For the dimer, a slightly V-shaped structure was computed, and intermolecular interactions are dominated by dispersion rather than hydrogen-bonding. The highest oscillator strength was computed for the transition to the S4 state, which deactivates within 4 ps to a lower-lying excited state.