![Author ORCID: We display the ORCID iD icon alongside authors names on our website to acknowledge that the ORCiD has been authenticated when entered by the user. To view the users ORCiD record click the icon. [opens in a new tab]](https://chemrxiv.org/engage/assets/public/chemrxiv/images/logos/orcid.png)
Abstract
The trihydrogen cation, H3+, is unique in the Universe. It serves as the primary proton reservoir, driving essential astrochemical reactions, and it functions as a thermostat for giant gas planets. H3+ has also remarkably low photodissociation rate, explained by its exceptionally high first electronic excitation energy (19.3 eV). Herein we reveal the key factors behind this high energy: (i) aromatic stabilization in its electronic ground state, (ii) antiaromatic destabilization in its first excited state, and (iii) a high nuclear-to-electronic charge ratio (+3 vs. -2). Through comparisons with analogous pi-conjugated carbocations, we find that ground state aromatic stabilization plus excited state antiaromatic destabilization raise the excitation energy of H3+ by 4.8 - 6.0 eV. Only with this increase can it fulfil its unique functions in space.
Supplementary materials
Title
Supplementary Material of "Deciphering the astrophotochemical ..."
Description
The SI contains:
Section S1: Computational details,
Section S2: Energies and geometries of H3+,
Section S3: Aromaticity of H3+, electronic properties,
Section S4: Aromaticity of H3+, magnetic properties,
Section S5: Protons-to-electrons ratios,
Section S6: Cyclopropenium cation (C3H3+),
Section S7: Supplementary references
Actions
