TY - JOUR
A1 - Picconi, David
T1 - Nonadiabatic quantum dynamics of the coherent excited state intramolecular proton transfer of 10-hydroxybenzo[h]quinoline
JF - Photochemical & photobiological sciences
N2 - The photoinduced nonadiabatic dynamics of the enol-keto isomerization of 10-hydroxybenzo[h]quinoline (HBQ) are studied computationally using high-dimensional quantum dynamics. The simulations are based on a diabatic vibronic coupling Hamiltonian, which includes the two lowest pi pi* excited states and a n pi* state, which has high energy in the Franck-Condon zone, but significantly stabilizes upon excited state intramolecular proton transfer. A procedure, applicable to large classes of excited state proton transfer reactions, is presented to parametrize this model using potential energies, forces and force constants, which, in this case, are obtained by time-dependent density functional theory. The wave packet calculations predict a time scale of 10-15 fs for the photoreaction, and reproduce the time constants and the coherent oscillations observed in time- resolved spectroscopic studies performed on HBQ. In contrast to the interpretation given to the most recent experiments, it is found that the reaction initiated by 1 pi pi* <- S-0 photoexcitation proceeds essentially on a single potential energy surface, and the observed coherences bear signatures of Duschinsky mode-mixing along the reaction path. The dynamics after the 2 pi pi* <- S-0 excitation are instead nonadiabatic, and the n pi* state plays a major role in the relaxation process. The simulations suggest a mainly active role of the proton in the isomerization, rather than a passive migration assisted by the vibrations of the benzoquinoline backbone.
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KW - Excited state proton transfer
KW - Quantum dynamics
KW - Nonadiabatic effects
KW - Spectroscopy
KW - Coherences
Y1 - 2021
U6 - https://doi.org/10.1007/s43630-021-00112-z
SN - 1474-905X
SN - 1474-9092
VL - 20
IS - 11
SP - 1455
EP - 1473
PB - Springer
CY - Heidelberg
ER -
TY - JOUR
A1 - Picconi, David
T1 - Quantum dynamics of the photoinduced charge separation in a symmetric donor-acceptor-donor triad
BT - the role of vibronic couplings, symmetry and temperature
JF - The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr
N2 - The photoinduced charge separation in a symmetric donor-acceptor-donor (D-A-D) triad is studied quantum mechanically using a realistic diabatic vibronic coupling model. The model includes a locally excited DA*D state and two charge-transfer states D(+)A(-)D and DA(-)D(+) and is constructed according to a procedure generally applicable to semirigid D-A-D structures and based on energies, forces, and force constants obtained by quantum chemical calculations. In this case, the electronic structure is described by time-dependent density functional theory, and the corrected linear response is used in conjunction with the polarizable continuum model to account for state-specific solvent effects. The multimode dynamics following the photoexcitation to the locally excited state are simulated by the hybrid Gaussian-multiconfigurational time-dependent Hartree method, and temperature effects are included using thermo field theory. The dynamics are connected to the transient absorption spectrum obtained in recent experiments, which is simulated and fully assigned from first principles. It is found that the charge separation is mediated by symmetry-breaking vibrations of relatively low frequency, which implies that temperature should be accounted for to obtain reliable estimates of the charge transfer rate.
Y1 - 2022
U6 - https://doi.org/10.1063/5.0089887
SN - 0021-9606
SN - 1089-7690
VL - 156
IS - 18
PB - AIP Publishing
CY - Melville
ER -
TY - JOUR
A1 - Mayer, Dennis
A1 - Picconi, David
A1 - Robinson, Matthew S.
A1 - Gühr, Markus
T1 - Experimental and theoretical gas-phase absorption spectra of thionated uracils
JF - Chemical physics : a journal devoted to experimental and theoretical research involving problems of both a chemical and physical nature
N2 - We present a comparative study of the gas-phase UV spectra of uracil and its thionated counterparts (2-thiouracil, 4-thiouracil and 2,4-dithiouracil), closely supported by time-dependent density functional theory calculations to assign the transitions observed. We systematically discuss pure gas-phase spectra for the (thio)uracils in the range of 200-400 nm (similar to 3.2-6.4 eV), and examine the spectra of all four species with a single theoretical approach. We note that specific vibrational modelling is needed to accurately determine the spectra across the examined wavelength range, and systematically model the transitions that appear at wavelengths shorter than 250 nm. Additionally, we find in the cases of 2-thiouracil and 2,4-dithiouracil, that the gas-phase spectra deviate significantly from some previously published solution-phase spectra, especially those collected in basic environments.
KW - Thiouracil
KW - Uracil
KW - UV-VIS Spectroscopy
KW - Excited-state calculations;
KW - TD-DFT
KW - Gas phase
Y1 - 2022
U6 - https://doi.org/10.1016/j.chemphys.2022.111500
SN - 0301-0104
VL - 558
PB - Elsevier
CY - Amsterdam
ER -
TY - GEN
A1 - Mayer, Dennis
A1 - Lever, Fabiano
A1 - Picconi, David
A1 - Metje, Jan
A1 - Ališauskas, Skirmantas
A1 - Calegari, Francesca
A1 - Düsterer, Stefan
A1 - Ehlert, Christopher
A1 - Feifel, Raimund
A1 - Niebuhr, Mario
A1 - Manschwetus, Bastian
A1 - Kuhlmann, Marion
A1 - Mazza, Tommaso
A1 - Robinson, Matthew Scott
A1 - Squibb, Richard James
A1 - Trabattoni, Andrea
A1 - Wallner, Måns
A1 - Saalfrank, Peter
A1 - Wolf, Thomas J. A.
A1 - Gühr, Markus
T1 - Following excited-state chemical shifts in molecular ultrafast x-ray photoelectron spectroscopy
T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2 - The conversion of photon energy into other energetic forms in molecules is accompanied by charge moving on ultrafast timescales. We directly observe the charge motion at a specific site in an electronically excited molecule using time-resolved x-ray photoelectron spectroscopy (TR-XPS). We extend the concept of static chemical shift from conventional XPS by the excited-state chemical shift (ESCS), which is connected to the charge in the framework of a potential model. This allows us to invert TR-XPS spectra to the dynamic charge at a specific atom. We demonstrate the power of TR-XPS by using sulphur 2p-core-electron-emission probing to study the UV-excited dynamics of 2-thiouracil. The method allows us to discover that a major part of the population relaxes to the molecular ground state within 220–250 fs. In addition, a 250-fs oscillation, visible in the kinetic energy of the TR-XPS, reveals a coherent exchange of population among electronic states.
T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1301
Y1 - 2022
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-577442
SN - 1866-8372
N1 - These authors contributed equally: D. Mayer, F. Lever.
A Publisher Correction to this article was published on 09 March 2022.
This article has been updated.
IS - 1301
ER -
TY - JOUR
A1 - Mayer, Dennis
A1 - Lever, Fabiano
A1 - Picconi, David
A1 - Metje, Jan
A1 - Ališauskas, Skirmantas
A1 - Calegari, Francesca
A1 - Düsterer, Stefan
A1 - Ehlert, Christopher
A1 - Feifel, Raimund
A1 - Niebuhr, Mario
A1 - Manschwetus, Bastian
A1 - Kuhlmann, Marion
A1 - Mazza, Tommaso
A1 - Robinson, Matthew Scott
A1 - Squibb, Richard James
A1 - Trabattoni, Andrea
A1 - Wallner, Måns
A1 - Saalfrank, Peter
A1 - Wolf, Thomas J. A.
A1 - Gühr, Markus
T1 - Following excited-state chemical shifts in molecular ultrafast x-ray photoelectron spectroscopy
JF - Nature Communications
N2 - The conversion of photon energy into other energetic forms in molecules is accompanied by charge moving on ultrafast timescales. We directly observe the charge motion at a specific site in an electronically excited molecule using time-resolved x-ray photoelectron spectroscopy (TR-XPS). We extend the concept of static chemical shift from conventional XPS by the excited-state chemical shift (ESCS), which is connected to the charge in the framework of a potential model. This allows us to invert TR-XPS spectra to the dynamic charge at a specific atom. We demonstrate the power of TR-XPS by using sulphur 2p-core-electron-emission probing to study the UV-excited dynamics of 2-thiouracil. The method allows us to discover that a major part of the population relaxes to the molecular ground state within 220–250 fs. In addition, a 250-fs oscillation, visible in the kinetic energy of the TR-XPS, reveals a coherent exchange of population among electronic states.
Y1 - 2022
U6 - https://doi.org/10.1038/s41467-021-27908-y
SN - 2041-1723
N1 - These authors contributed equally: D. Mayer, F. Lever.
A Publisher Correction to this article was published on 09 March 2022.
This article has been updated.
VL - 13
PB - Springer Nature
CY - Berlin
ER -
TY - JOUR
A1 - Mayer, Dennis
A1 - Lever, Fabiano
A1 - Picconi, David
A1 - Metje, Jan
A1 - Ališauskas, Skirmantas
A1 - Calegari, Francesca
A1 - Düsterer, Stefan
A1 - Ehlert, Christopher
A1 - Feifel, Raimund
A1 - Niebuhr, Mario
A1 - Manschwetus, Bastian
A1 - Kuhlmann, Marion
A1 - Mazza, Tommaso
A1 - Robinson, Matthew Scott
A1 - Squibb, Richard J.
A1 - Trabattoni, Andrea
A1 - Wallner, Måns
A1 - Saalfrank, Peter
A1 - Wolf, Thomas J. A.
A1 - Gühr, Markus
T1 - Following excited-state chemical shifts in molecular ultrafast x-ray photoelectron spectroscopy
JF - Nature communications
N2 - Imaging the charge flow in photoexcited molecules would provide key information on photophysical and photochemical processes. Here the authors demonstrate tracking in real time after photoexcitation the change in charge density at a specific site of 2-thiouracil using time-resolved X-ray photoelectron spectroscopy. The conversion of photon energy into other energetic forms in molecules is accompanied by charge moving on ultrafast timescales. We directly observe the charge motion at a specific site in an electronically excited molecule using time-resolved x-ray photoelectron spectroscopy (TR-XPS). We extend the concept of static chemical shift from conventional XPS by the excited-state chemical shift (ESCS), which is connected to the charge in the framework of a potential model. This allows us to invert TR-XPS spectra to the dynamic charge at a specific atom. We demonstrate the power of TR-XPS by using sulphur 2p-core-electron-emission probing to study the UV-excited dynamics of 2-thiouracil. The method allows us to discover that a major part of the population relaxes to the molecular ground state within 220-250 fs. In addition, a 250-fs oscillation, visible in the kinetic energy of the TR-XPS, reveals a coherent exchange of population among electronic states.
Y1 - 2022
U6 - https://doi.org/10.1038/s41467-021-27908-y
SN - 2041-1723
N1 - Publisher correction: https://doi.org/10.1038/s41467-022-28584-2
VL - 13
IS - 1
PB - Nature Research
CY - Berlin
ER -