Mainz 2026 – scientific programme
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MO: Fachverband Molekülphysik
MO 30: Poster – Molecular Spectroscopy
MO 30.19: Poster
Thursday, March 5, 2026, 17:00–19:00, Philo 1. OG
Electronic Spectra of Doped Diamondoid Cations — •Parker Crandall, Ronja Schramm, Sebastian Völz, Domenik Schleier, and Otto Dopfer — Institut für Physik und Astronomie, Technische Universität Berlin, Berlin, Germany
We present our recently measured gas-phase photoelectron spectra (PES) of doped (cage-modified) diamondoids, namely 2-oxaadamantane, 2-thiaadamantane, and urotropine, to investigate the excited electronic states of their respective cations. These are interpreted with the aid of quantum chemical calculations and compared to the PES spectra of previously measured diamondoids. Heteroatom substitution within the carbon-cage network yields large band gaps between the ground and first excited states. Furthermore, vibronic fine structure is observed in the higher energy bands that is not observed in the spectra of the bare and functionalized diamondoids. Electronic photodissociation (EPD) spectroscopy reveals that in the case of urotropine+, resolved vibronic structure attributed to the D3(2A1)←D0(2A1) electronic transition appears at a band origin of 29,990 cm−1 (333.4 nm) and grows increasingly more congested toward higher photon energy, suggesting considerable geometric distortion upon electronic excitation of the Jahn-Teller distorted ground electronic state. These measurements provide critical reference data for astronomical searches in the pursuit of a broader understanding of the chemical inventory of the interstellar medium.
Keywords: Spectroscopy; Astrochemistry; Diamondoids; Photoelectron; Photodissociation