Charge-Transfer-Induced Predissociation in Rydberg States of Molecular Cations: MgAr+
| Autor: | Wehrli, Dominik, Génévriez, Matthieu, Knecht, Stefan, Reiher, Markus, Merkt, Frédéric |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | The Journal of Physical Chemistry A, 125 (31) The journal of physical chemistry The Journal of Physical Chemistry. a |
| ISSN: | 1089-5639 1520-5215 |
| DOI: | 10.1021/acs.jpca.1c03859 |
| Popis: | Very little is known about the Rydberg states of molecular cations, i.e., Rydberg states having a doubly charged ion core. With the example of MgAr+, we present general features of the structure and dynamics of the Rydberg states of molecular cations, which we find are subject to the process of charge-transfer-induced predissociation. Our study focuses on the spectrum of low-n Rydberg states with potential-energy functions associated with the Mg+(3d and 4s) + Ar(S-1(0)) dissociation asymptotes. In particular, we have recorded spectra of the 3d pi(Omega') (Omega' = 1/2, 3/2) Rydberg states, extending from the lowest (v' = 0) vibrational levels to their dissociation limits. This spectral range encompasses the region where the onset of predissociation by interaction with the mostly repulsive (2)Sigma and (2)Pi charge-transfer states associated with the Mg(3s(2)) + Ar+(P-2(1/2,3/2)) dissociation asymptotes is observed. This interaction leads to very strong perturbations of the 3d pi Rydberg states of MgAr+, revealed by vibrational progressions exhibiting large and rapid variations of the vibrational intervals, line widths, and spin-orbit splittings. We attribute the anomalous sign and magnitude of the spin-orbit coupling constant of the 3dp state to the interaction with a (2)Pi Rydberg state correlating to the Mg+(4p) + Ar(S-1(0)) dissociation limit. To analyze our spectra and elucidate the underlying process of charge-transfer-induced predissociation, we implemented a model that allowed us to derive the potential-energy functions of the charge-transfer states and to quantitatively reproduce the experimental results. This analysis characterizes the main features of the dynamics of the Rydberg series converging to the ground state of MgAr2+. We expect that the results and analysis reported here are qualitatively valid for a broader range of singly charged molecular cations, which are inherently prone to charge-transfer interactions. The Journal of Physical Chemistry A, 125 (31) ISSN:1089-5639 ISSN:1520-5215 |
| Databáze: | OpenAIRE |
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