|
|||||
|
|
Photodetachment of Deprotonated R-Mandelic Acid: The Role of Proton Delocalization on the Radical Stability |
|
| Authors: | Franco L Molina Dr Rafael A Jara-Toro Dr Jennifer A Noble Dr Claude Dedonder-Lardeux Dr Christophe Jouvet Prof Gustavo A Pino |
| Institution: | 1. INFIQC: Instituto de Investigaciones en Fisicoquímica de Córdoba (CONICET – UNC) –, Haya de la Torre s/n, Ciudad Universitaria, X5000HUA Córdoba, Argentina
Departamento de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba –, Haya de la Torre y Medina Allende, Ciudad Universitaria, X5000HUA Córdoba, Argentina Centro Láser de Ciencias Moleculares –, Universidad Nacional de Córdoba, Haya de la Torre s/n, Pabellón Argentina, Ciudad Universitaria, X5000HUA Córdoba, Argentina;2. Physique des Interactions Ioniques et Moléculaires (PIIM), CNRS, Aix-Marseille Université, 13397 Marseille, France;3. INFIQC: Instituto de Investigaciones en Fisicoquímica de Córdoba (CONICET – UNC) –, Haya de la Torre s/n, Ciudad Universitaria, X5000HUA Córdoba, Argentina |
| Abstract: | The photodetachment and stability of R-Mandelate, the deprotonated form of the R-Mandelic acid, was investigated by observing the neutral species issued from either simple photodetachment or dissociative photodetachment in a cold anions set-up. R-Mandalate has the possibility to form an intramolecular ionic hydrogen-bond between adjacent hydroxyl and carboxylate groups. The potential energy surface along the proton transfer (PT) coordinate between both groups (O?…H+…?OCO) features a single local minima, with the proton localized on the O? group (OH…?OCO). However, the structure with the proton localized on the ?OCO group (O?…HOCO) is also observed because it falls within the extremity of the vibrational wavefunction of the OH…?OCO isomer along the PT coordinate. The stability of the corresponding radicals, produced upon photodetachment, is strongly dependent on the position of the proton in the anion: the radicals produced from the OH…?OCO isomer decarboxylate without barrier, while the radicals produced from the O?…HOCO isomer are stable. |
| Keywords: | Cold anions spectroscopy Density functional calculations Laser spectroscopy Mass spectrometry Nuclear quantum effects |