scholarly journals Structural dynamics of photochemical reactions probed by time-resolved photoelectron spectroscopy using high harmonic pulses

2016 ◽  
Vol 194 ◽  
pp. 147-160 ◽  
Author(s):  
Ryo Iikubo ◽  
Taro Sekikawa ◽  
Yu Harabuchi ◽  
Tetsuya Taketsugu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Ring Opening ◽  
Potential Energy Surfaces ◽  
High Harmonic ◽  
Photochemical Reactions ◽  
Photoelectron Spectra ◽  
Time Resolved ◽  
Photon Excitation ◽  
Energy Surfaces ◽  
Sigma Bond

Femtosecond ring-opening dynamics of 1,3-cyclohexadiene (CHD) in gas phase upon two-photon excitation at 400 nm (=3.1 eV) was investigated by time-resolved photoelectron spectroscopy using 42 nm (=29.5 eV) high harmonic photons probing the dynamics of the lower-lying occupied molecular orbitals (MOs), which are the fingerprints of the molecular structure. After 500 fs, the photoelectron intensity of the MO constituting the CC sigma bond (σCC) of CHD was enhanced, while that of the MO forming the C–C sigma bond (σCC) of CHD was decreased. The changes in the photoelectron spectra suggest that the ring of CHD opens to form a 1,3,5-hexatriene (HT) after 500 fs. The dynamics of the σCC and σCC bands between 200 and 500 fs reflects the ring deformation to a conical intersection between the 21A and 11A potential energy surfaces prior to the ring-opening reaction.

scholarly journals Ultrafast extreme ultraviolet photoemission without space charge

2019 ◽  
Vol 205 ◽  
pp. 02014
Author(s):  
Peng Zhao ◽  
Christopher Corder ◽  
Jin Bakalis ◽  
Xinlong Li ◽  
Matthew D. Kershis ◽  
...  
Keyword(s):  
Space Charge ◽  
Photoelectron Spectroscopy ◽  
Extreme Ultraviolet ◽  
High Harmonic ◽  
Photoelectron Spectra ◽  
Time Resolved ◽  
Record Time ◽  
Free Sample ◽  
Harmonic Source

We present photoelectron spectroscopy experiments using an 88 MHz cavityenhanced high-harmonic source operating from 8 to 40 eV. Nanoampere space-charge free sample photo currents enable us to record time-resolved photoelectron spectra from weakly excited samples.

scholarly journals Time-resolved high-harmonic spectroscopy of ultrafast ring-opening of 1,3-cyclohexadiene

2019 ◽  
Vol 205 ◽  
pp. 09017
Author(s):  
Keisuke Kaneshima ◽  
Yuki Ninota ◽  
Taro Sekikawa
Keyword(s):  
Ring Opening ◽  
High Harmonic ◽  
Harmonic Signal ◽  
Photochemical Reactions ◽  
Photon Absorption ◽  
Nuclear Dynamics ◽  
Time Resolved ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Bond Rearrangement

We report, to the best of our knowledge, the first time-resolved high-harmonic spectroscopy (TR-HHS) study of a chemical bond rearrangement. We investigate the transient change of the high-harmonic signal from 1,3-cyclohexadiene (CHD), which undergoes ring-opening and isomerizes to 1,3,5-hexatriene (HT) upon photoexcitation. By associating the variation in the harmonic yield to the changes in the electronic state and vibrational frequencies of the molecule due to isomerization, we find that the CHD excited via two-photon absorption of 3.1 eV photons isomerizes to HT, i.e., ring-opening occurs, around 400 fs after the excitation. The present results demonstrate that TR-HHS, which can track both electronic and nuclear dynamics, is a powerful tool for studying ultrafast photochemical reactions.

scholarly journals Effects of probe energy and competing pathways on time-resolved photoelectron spectroscopy: the ring-opening of 1,3-cyclohexadiene

2018 ◽  
Vol 20 (26) ◽  
pp. 17714-17726 ◽  
Author(s):  
Maria Tudorovskaya ◽  
Russell S. Minns ◽  
Adam Kirrander
Keyword(s):  
Molecular Dynamics ◽  
Photoelectron Spectroscopy ◽  
Ring Opening ◽  
Photoelectron Spectra ◽  
Quantum Molecular Dynamics ◽  
Time Resolved ◽  
Model Based ◽  
Competing Pathways

Photoelectron spectra for the ring-opening dynamics of 1,3-cyclohexadiene are studied using a model based on quantum molecular dynamics and the Dyson orbital approach.

Excited State Tracking During the Relaxation of Coordination Compounds

2018 ◽  
Author(s):  
Juan Sanz García ◽  
Martial Boggio-Pasqua ◽  
Ilaria Ciofini ◽  
Marco Campetella
Keyword(s):  
Excited State ◽  
Excited States ◽  
Potential Energy Surfaces ◽  
Photochemical Reactions ◽  
Complex Nature ◽  
Electronic Excited States ◽  
Ruthenium Nitrosyl ◽  
State Tracking ◽  
Energy Surfaces ◽  
Electronic Wavefunction

<div>The ability to locate minima on electronic excited states (ESs) potential energy surfaces (PESs) both in the case of bright and dark states is crucial for a full understanding of photochemical reactions. This task has become a standard practice for small- to medium-sized organic chromophores thanks to the constant developments in the field of computational photochemistry. However, this remains a very challenging effort when it comes to the optimization of ESs of transition metal complexes (TMCs), not only due to the presence of several electronic excited states close in energy, but also due to the complex nature of the excited states involved. In this article, we present a simple yet powerful method to follow an excited state of interest during a structural optimization in the case of TMC, based on the use of a compact hole-particle representation of the electronic transition, namely the natural transition orbitals (NTOs). State tracking using NTOs is unambiguously accomplished by computing the mono-electronic wavefunction overlap between consecutive steps of the optimization. Here, we demonstrate that this simple but robust procedure works not only in the case of the cytosine but also in the case of the ES optimization of a ruthenium-nitrosyl complex which is very problematic with standard approaches.</div>

THEORETICAL TRANSITION PROBABILITIES FOR THE $\tilde{A}^{2}A_{1} -\tilde{X}^{2}B_{1}$ SYSTEM OF H2O+ AND D2O+ AND RELATED FRANCK–CONDON FACTORS BASED ON GLOBAL POTENTIAL ENERGY SURFACES

2005 ◽  
Vol 04 (01) ◽  
pp. 225-245 ◽  
Author(s):  
IKUO TOKUE ◽  
KATSUYOSHI YAMASAKI ◽  
SATOSHI MINAMINO ◽  
SHINKOH NANBU
Keyword(s):  
Potential Energy ◽  
Photoelectron Spectroscopy ◽  
Potential Energy Surfaces ◽  
Least Squares Method ◽  
Transition Probabilities ◽  
Three Dimensional ◽  
Equilibrium Geometry ◽  
Condon Factors ◽  
Energy Surfaces ◽  
Franck Condon

To elucidate the ionization dynamics, in particular the vibrational distribution, of H 2 O +(Ã) produced by photoionization and the Penning ionization of H 2 O and D 2 O with He *(2 3S) atoms, Franck–Condon factors (FCFs) were given for the [Formula: see text] ionization, and the transition probabilities were presented for the [Formula: see text] emission. The FCFs were obtained by quantum vibrational calculations using the three-dimensional potential energy surfaces (PESs) of [Formula: see text] and [Formula: see text] electronic states. The global PESs were determined by the multi-reference configuration interaction calculations with the Davidson correction and the interpolant moving least squares method combined with the Shepard interpolation. The obtained FCFs exhibit that the [Formula: see text] state primarily populates the vibrational ground state, as its equilibrium geometry is almost equal to that of [Formula: see text], while the bending mode (ν2) is strongly enhanced for the H 2 O +(Ã) state; the maximums in the population of H 2 O + and D 2 O + are approximately v2 = 11–12 and 15–17, respectively. These results are consistent with the distributions observed by photoelectron spectroscopy. Transition probabilities for the [Formula: see text] system of H 2 O + and D 2 O + show that the bending progressions consist primarily of the [Formula: see text] emission, with combination bands from the (1, v′2 = 4–8, 0) level being next most important.

Potential energy surfaces for the photochemical reactions Ca*+H2→CaH+H

2002 ◽  
Vol 116 (2) ◽  
pp. 589-593 ◽  
Author(s):  
Kyoung Hoon Kim ◽  
Hyo Sug Lee ◽  
Yoon Sup Lee ◽  
Gwang-Hi Jeung
Keyword(s):  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Photochemical Reactions ◽  
Energy Surfaces
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