Experimental proof of strong $Π$-$Σ$ mixing in the Renner-Teller and Pseudo-Jahn-Teller affected CCH$^+$ ($^3Π$) ion
Fuente:
arXiv
Guardado en:
| Autores principales: | , , , , , , , , , , |
|---|---|
| Formato: | Preprint |
| Publicado: |
2026
|
| Materias: | |
| Acceso en línea: | |
| Etiquetas: |
Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
|
| _version_ | 1866917398632726528 |
|---|---|
| author | Steenbakkers, Kim Changala, P. Bryan Silva, Weslley G. D. P. Stanton, John F. Lipparini, Filippo Gauss, Jürgen Asvany, Oskar Groenenboom, Gerrit C. Redlich, Britta Schlemmer, Stephan Brünken, Sandra |
| author_facet | Steenbakkers, Kim Changala, P. Bryan Silva, Weslley G. D. P. Stanton, John F. Lipparini, Filippo Gauss, Jürgen Asvany, Oskar Groenenboom, Gerrit C. Redlich, Britta Schlemmer, Stephan Brünken, Sandra |
| contents | The ethynyl radical cation, CCH$^+$ ($^3Π$), offers a unique system for fundamental spectroscopic studies of non-adiabatic effects due to its open-shell linear structure and the presence of a low-lying $^3Σ^-$ state, which induces notable perturbations in the (ro-)vibrational spectrum. To probe these effects, we recorded the broadband vibrational spectrum of CCH$^+$ from 350-3450 cm$^{-1}$ using leak-out spectroscopy. The spectrum reveals a complex splitting pattern in the CCH bending mode, attributed to Renner-Teller and pseudo-Jahn-Teller coupling effects between the $^3 Π$ and $^3 Σ^-$ electronic states. A three-state diabatic model, validated here against high-resolution IR data of the CH stretching mode, facilitated assignments within the broadband infrared (IR) spectrum, including an additional $Π$ vibronic feature observed in the aforementioned high-resolution spectrum. Our results highlight a pronounced sensitivity of the splitting pattern to the $Π$-$Σ$ energy gap, with couplings so large that even the zero-point vibrational motion of the bending vibration is sufficient to disrupt the vibronic structure of this ion. This compact ion, with strong coupling effects and high-quality spectroscopic data, serves as an exemplary system for evaluating non-adiabatic models. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2604_09203 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Experimental proof of strong $Π$-$Σ$ mixing in the Renner-Teller and Pseudo-Jahn-Teller affected CCH$^+$ ($^3Π$) ion Steenbakkers, Kim Changala, P. Bryan Silva, Weslley G. D. P. Stanton, John F. Lipparini, Filippo Gauss, Jürgen Asvany, Oskar Groenenboom, Gerrit C. Redlich, Britta Schlemmer, Stephan Brünken, Sandra Chemical Physics The ethynyl radical cation, CCH$^+$ ($^3Π$), offers a unique system for fundamental spectroscopic studies of non-adiabatic effects due to its open-shell linear structure and the presence of a low-lying $^3Σ^-$ state, which induces notable perturbations in the (ro-)vibrational spectrum. To probe these effects, we recorded the broadband vibrational spectrum of CCH$^+$ from 350-3450 cm$^{-1}$ using leak-out spectroscopy. The spectrum reveals a complex splitting pattern in the CCH bending mode, attributed to Renner-Teller and pseudo-Jahn-Teller coupling effects between the $^3 Π$ and $^3 Σ^-$ electronic states. A three-state diabatic model, validated here against high-resolution IR data of the CH stretching mode, facilitated assignments within the broadband infrared (IR) spectrum, including an additional $Π$ vibronic feature observed in the aforementioned high-resolution spectrum. Our results highlight a pronounced sensitivity of the splitting pattern to the $Π$-$Σ$ energy gap, with couplings so large that even the zero-point vibrational motion of the bending vibration is sufficient to disrupt the vibronic structure of this ion. This compact ion, with strong coupling effects and high-quality spectroscopic data, serves as an exemplary system for evaluating non-adiabatic models. |
| title | Experimental proof of strong $Π$-$Σ$ mixing in the Renner-Teller and Pseudo-Jahn-Teller affected CCH$^+$ ($^3Π$) ion |
| topic | Chemical Physics |
| url | https://arxiv.org/abs/2604.09203 |