Time-resolved vacuum-ultraviolet photoelectron spectroscopy of the à ¹Aᵤ state of acetylene

Razmus, Weronika O.; Prlj, Antonio; Seifert, Nathan A.; Bonanomi, Matteo; Callegari, Carlo; Danailov, Miltcho; Decleva, Piero; Demidovich, Alexander; De Ninno, Giovanni; Devetta, Michele; Faccialà, Davide; Feifel, Raimund; Giannessi, Luca; Piteša, Tomislav; Powis, Ivan; Raimondi, Lorenzo; Reid, Katharine L.; Ribič, Primož Rebernik; Spezzani, Carlo; Squibb, Richard J.; Thompson, James O. F.; Plekan, Oksana; Vozzi, Caterina; Warne, Emily M.; Zangrando, Marco; Prince, Kevin C.; Di Fraia, Michele; Holland, David M. P.; Minns, Russell S.; Došlić, Nađa; Pratt, Stephen T.

Abstract

Ultrafast time-resolved photoelectron spectra are reported for the vacuum-ultraviolet (VUV) photoionization of acetylene following excitation to the à ¹Aᵤ state via UV absorption at 200 nm. The excitation energy lies above the lowest dissociation threshold to C₂H X̃ ²Σ⁺ + H, as well as above the threshold for adiabatic dissociation of the à ¹Aᵤ state to form C₂H (⁠à ²Π) ⁺ H. The time-dependent mass spectra and photoelectron spectra provide insight into the intramolecular decay processes of the à ¹Aᵤ state. In addition, photoelectron spectra of the à ¹Aᵤ state with VUV light access both the X̃ ²Πu and à ²Σ₉⁺ states of the ion, as well as the predicted, but previously unobserved, 1 ²Π₉ state, which corresponds to a two-hole, one-particle configuration that lies in close proximity to the à ²Σg⁺ state. The 1 ²Π₉ state is split into ²A2 + ²B2 and ²A₉⁺ ²B₉ states in the cis and trans configurations, respectively. Electronic structure calculations, along with trajectory calculations, reproduce the principal features of the experimental data and confirm the assignment of the 1 ²Π₉ state.

Citation

Razmus, W. O., Prlj, A., Seifert, N. A., Bonanomi, M., Callegari, C., Danailov, M., Decleva, P., Demidovich, A., De Ninno, G., Devetta, M., Faccialà, D., Feifel, R., Giannessi, L., Piteša, T., Powis, I., Raimondi, L., Reid, K. L., Ribič, P. R., Spezzani, C., Squibb, R. J., …Pratt, S. T. (2025). Time-resolved vacuum-ultraviolet photoelectron spectroscopy of the à ¹Aᵤ state of acetylene. Journal of Chemical Physics, 162(5), Article 054310. https://doi.org/10.1063/5.0241392

• Journal Article Type: Article
• Acceptance Date: Jan 9, 2025
• Online Publication Date: Feb 5, 2025
• Publication Date: Feb 7, 2025
• Deposit Date: Feb 6, 2025
• Publicly Available Date: Feb 6, 2025
• Journal: Journal of Chemical Physics
• Print ISSN: 0021-9606
• Electronic ISSN: 1089-7690
• Publisher: American Institute of Physics
• Peer Reviewed: Peer Reviewed
• Volume: 162
• Issue: 5
• Article Number: 054310
• DOI: https://doi.org/10.1063/5.0241392
• Public URL: https://nottingham-repository.worktribe.com/output/45039813
• Publisher URL: https://pubs.aip.org/aip/jcp/article-abstract/162/5/054310/3333660/Time-resolved-vacuum-ultraviolet-photoelectron?redirectedFrom=fulltext