Person: Marggi PoullaĆn, Sonia
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First Name
Sonia
Last Name
Marggi PoullaĆn
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias QuĆmicas
Department
QuĆmica FĆsica
Area
QuĆmica FĆsica
Identifiers
16 results
Search Results
Now showing 1 - 10 of 16
Item Imaging the photodissociation dynamics of internally excited ethyl radicals from high Rydberg states(Physical Chemistry Chemical Physics, 2023) Rubio Lago, Luis; Chicharro, David V.; Marggi PoullaĆn, Sonia; Zanchet, Alexandre; Koumarianou, Greta; Glodic, Pavle; Samartzis, Peter C.; GarcĆa Vela, Alberto; BaƱares Morcillo, LuisThe site-specific hydrogen-atom elimination mechanism previously reported for photoexcited ethyl radicals (CH3CH2) [D. V. Chicharro et al., Chem. Sci., 2019, 10, 6494] is interrogated in the photodissociation of the ethyl isotopologues CD3CD2, CH3CD2 and CD3CH2 through the velocity map imaging (VMI) detection of the produced hydrogen- and deuterium-atoms. The radicals, generated in situ from photolysis of a precursor using the same laser pulse employed in their excitation to Rydberg states, decompose along the Ca-H/D and Cb-H/D reaction coordinates through coexisting statistical and site-specific mechanisms. The experiments are carried out at two excitation wavelengths, 201 and 193 nm. The comparison between both sets of results provides accurate information regarding the primary role in the site-specific mechanism of the radical internal reservoir. Importantly, at 193 nm excitation, higher energy dissociation channels (not observed at 201 nm) producing low-recoil H/Datoms become accessible. High-level ab initio calculations of potential energy curves and the corresponding non-adiabatic interactions allow us to rationalize the experimental results in terms of competitive non-adiabatic decomposition paths. Finally, the adiabatic behavior of the conical intersections in the face of several vibrational modes ā the so-called vibrational promoting modes ā is discussed.Item Halogen-atom effect on the ultrafast photodissociation dynamics of the dihalomethanes CH2 ICl and CH2 BrI(Physical Chemistry Chemical Physics, 2018) Murillo SĆ”nchez, Marta Luisa; Marggi PoullaĆn, Sonia; Bajo GonzĆ”lez, Juan JosĆ©; Corrales Castellanos, MarĆa Eugenia; GonzĆ”lez VĆ”zquez, JesĆŗs; Sola Reija, Ignacio; BaƱares Morcillo, LuisReal time photodissociation of dihalomethanes has been measured by femtosecond velocity map imaging to disentangle the effect of the halogen-atom on the carbonāiodine cleavage dynamics.Item Femtosecond XUV induced dynamics of the methyl iodide cation(2019) Reitsma, Geert; Murillo SĆ”nchez, Marta Luisa; Nalda MĆguez, Rebeca de; Corrales Castellanos, MarĆa Eugenia; Marggi PoullaĆn, Sonia; GonzĆ”lez VĆ”zquez, JesĆŗs; Vrakking, Marc J.J.; BaƱares Morcillo, Luis; Kornilov, Oleg; Cerullo, G.; Ogilvie, J.; KƤrtner, F.; Khalil, M.; Li, R.Ultrashort XUV wavelength-selected pulses obtained with high harmonic generation are used to study the dynamics of molecular cations with state-to-state resolution. We demonstrate this by XUV pump - IR probe experiments on CH3I+ cations and identify both resonant and non-resonant dynamics.Item Revealing electronic state-switching at conical intersections in alkyl iodides by ultrafast XUV transient absorption spectroscopy(Nature Communications, 2020) Chang, Kristina; Reduzzi, Maurizio; Wang, Han; Marggi PoullaĆn, Sonia; Kobayashi, Yuki; Barreau, Lou; Prendergast, David; Neumark, Daniel; Leone, StephenConical intersections between electronic states often dictate the chemistry of photoexcited molecules. Recently developed sources of ultrashort extreme ultraviolet (XUV) pulses tuned to element-specific transitions in molecules allow for the unambiguous detection of electronic state-switching at a conical intersection. Here, the fragmentation of photoexcited iso-propyl iodide and tert-butyl iodide molecules (i-C3H7I and t-C4H9I) through a conical intersection between 3Q0/1Q1 spināorbit states is revealed by ultrafast XUV transient absorption measuring iodine 4d core-to-valence transitions. The electronic state-sensitivity of the technique allows for a complete mapping of molecular dissociation from photoexcitation to photoproducts. In both molecules, the sub-100 fs transfer of a photoexcited wave packet from the 3Q0 state into the 1Q1 state at the conical intersection is captured. The results show how differences in the electronic state-switching of the wave packet in i-C3H7I and t-C4H9I directly lead to differences in the photoproduct branching ratio of the two systems.Item Visualizing coherent vibrational motion in the molecular iodine B state using ultrafast XUV transient-absorption spectroscopy(Physical Review A, 2021) Marggi PoullaĆn, Sonia; Kobayashi, Yuki; Chang, Kristina; Leone, StephenAttosecond probing of core-level electronic transitions in molecules provides a sensitive tool for real-time observation of chemical dynamics. Here, we employ ultrafast extreme-ultraviolet (XUV) transient-absorption spectroscopy to investigate the excited state electronic and nuclear dynamics in a prototype molecule, I2. A few-femtosecond visible pump pulse is employed to excite the I2 molecule and an attosecond XUV pulse is used to probe the dynamics through iodine-4d core-to-valence transitions. A highly extended vibrational wave packet (Ī½ā²=10ā50,Ī½ā²max=25) is prepared by one-photon absorption in the valence excited B3Ī 0+u state of I2 and its motion is directly mapped due to the strong shift of the XUV core-level transition with internuclear separation. Through the imaging of this vibrational motion, we directly reconstruct the transition energy between the valence and the core-excited states as a function of internuclear distance. Besides single-photon dynamics, distinct direct dissociation pathways arising from two-photon pump absorption are also revealed.Item Threshold Photoelectron Spectroscopy of the CH2I, CHI, and CI Radicals(The Journal of Physical Chemistry A, 2021) Chicharro, David V.; Hrodmarsson, Helgi Rafn; Bouallagui, Aymen; Zanchet, Alexandre; Loison, Jean-Christophe; GarcĆa, Gustavo A.; GarcĆa Vela, Alberto; BaƱares Morcillo, Luis; Marggi PoullaĆn, SoniaVUV photoionization of the CHnI radicals (with n = 0, 1, and 2) is investigated by means of synchrotron radiation coupled with a double imaging photoion-photoelectron coincidence spectrometer. Photoionization efficiencies and threshold photoelectron spectra (TPES) for photon energies ranging between 9.2 and 12.0 eV are reported. An adiabatic ionization energy (AIE) of 8.334 Ā± 0.005 eV is obtained for CH2I, which is in good agreement with previous results [8.333 Ā± 0.015 eV, SztĆ”ray et al. J. Chem. Phys. 2017, 147, 013944], while for CI an AIE of 8.374 Ā± 0.005 eV is measured for the first time and a value of ā¼8.8 eV is estimated for CHI. Ab initio calculations have been carried out for the ground state of the CH2I radical and for the ground state and excited states of the radical cation CH2I + , including potential energy curves along the CāI coordinate. FranckāCondon factors are calculated for transitions from the CH2I(XĢ 2 B1) ground state of the neutral radical to the ground state and excited states of the radical cation. The TPES measured for the CH2I radical shows several structures that correspond to the photoionization into excited states of the radical cation and are fully assigned on the basis of the calculations. The TPES obtained for the CHI is characterized by a broad structure peaking at 9.335 eV, which could be due to the photoionization from both the singlet and the triplet states and into one or more electronic states of the cation. A vibrational progression is clearly observed in the TPES for the CI radical and a frequency for the CāI stretching mode of 760 Ā± 60 cmā1 characterizing the CI+ electronic ground state has been extracted.Item Femtosecond predissociation dynamics of ethyl iodide in the B-band(Physical Chemistry Chemical Physics, 2019) Murillo SĆ”nchez, Marta Luisa; Marggi PoullaĆn, Sonia; Loriot, Vincent; Corrales, Maria Eugenia; BaƱares Morcillo, LuisFemtosecond velocity map imaging to disentangle the electronic predissociation of ethyl iodide in the B-band.Item Femtosecond photodissociation dynamics of chloroiodomethane in the first absorption band(Chemical Physics Letters, 2017) Murillo SĆ”nchez, Marta Luisa; Marggi PoullaĆn, Sonia; GonzĆ”lez-VĆ”zquez, JesĆŗs; Corrales, Maria Eugenia; Balerdi, Garikoitz; BaƱares Morcillo, LuisThe real time photodissociation of chloroiodomethane (CH2ICl) in the first absorption band at 268 nm is reported in comparison with the well-known methyl iodide (CH3I) in order to investigate the halogen-atom substituent effect on the time-resolved photodynamics of halomethanes. Femtosecond velocity map imaging measurements in conjunction with resonance enhanced multiphoton ionization (REMPI) to detect the iodine fragments have been performed to obtain translational energy, angular distributions and the photodissociation reaction times. High level ab initio and on-the-fly trajectory calculations have been carried out to rationalize the experimental results in terms of the excited states involved and the dissociation mechanisms.- Project number: PIMCD378/23-24
Item InnovaciĆ³n sobre la docencia y evaluaciĆ³n del laboratorio de QuĆmica FĆsica I(2024) Omiste Romero, Juan JosĆ©; Ahijado GuzmĆ”n, RubĆ©n; BlĆ”zquez FernĆ”ndez, Samuel; Caselli, Niccolo; DĆaz Blanco, Cristina; Guerrero MartĆnez, AndrĆ©s; HernĆ”ndez DĆaz, MarĆa Yolanda; Labrador PĆ”ez, LucĆa; Marggi PoullaĆn, Sonia; Pulido Lamas, Cintia; SĆ”nchez BenĆtez, Francisco Javier; Sola Reija, Ignacio; SuardĆaz DelrĆo, Reynier; Izquierdo Ruiz, Fernando; Lobato FernĆ”ndez, Ćlvaro; SĆ”nchez GonzĆ”lez, Julia Item Photodissociation dynamics of bromoiodomethane from the first and second absorption bands. A combined velocity map and slice imaging study(Physical Chemistry Chemical Physics, 2018) Marggi PoullaĆn, Sonia; Chicharro, David ; Navarro, Eduardo; Rubio-Lago, Luis; GonzĆ”lez-VĆ”zquez, JesĆŗs; BaƱares Morcillo, LuisThe photodissociation dynamics of bromoiodomethane (CH2BrI) have been investigated at the maximum of the first A and second Aā² absorption bands, at 266 and 210 nm excitation wavelengths, respectively, using velocity map and slice imaging techniques in combination with a probe detection of both iodine and bromine fragments, I(2P3/2), I*(2P1/2), Br(2P3/2) and Br*(2P1/2) via (2 + 1) resonance enhanced multiphoton ionization. Experimental results, i.e. translational energy and angular distributions, are reported and discussed in conjunction with high level ab initio calculations of potential energy curves and absorption spectra. The results indicate that in the A-band, direct dissociation through the 5Aā² excited state leads to the I(2P3/2) channel while I*(2P1/2) atoms are produced via the 5Aā² ā 4Aā²/4Aā²ā² nonadiabatic crossing. The presence of Br and Br* fragments upon excitation to the A-band is attributed to indirect dissociation via a curve crossing between the 5Aā² with upper excited states such as the 9Aā². The Aā²-band is characterized by a strong photoselectivity leading exclusively to the Br(2P3/2) and Br*(2P1/2) channels, which are likely produced by dissociation through the 9Aā² excited state. Avoided crossings between several excited states from both the A and Aā² bands entangle however the possible reaction pathways.