Pump-probe photoionization has been used to map the relaxation processes taking place from highly vibrationally excited levels of the S(2) state of azulene, populated directly or via internal conversion from the S(4) state. Photoelectron spectra obtained by 1+2(') two-color time-resolved photoelectron imaging are invariant (apart from in intensity) to the pump-probe time delay and to the pump wavelength. This reveals a photoionization process which is driven by an unstable electronic state (e.g., doubly excited state) lying below the ionization potential. This state is postulated to be populated by a probe transition from S(2) and to rapidly relax via an Auger-like process onto highly vibrationally excited Rydberg states. This accounts for the time invariance of the photoelectron spectrum. The intensity of the photoelectron spectrum is proportional to the population in S(2). An exponential energy gap law is used to describe the internal conversion rate from S(2) to S(0). The vibronic coupling strength is found to be larger than 60+/-5 microeV.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1063/1.2913167 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Crystal Lattice-Induced Stress modulates Photoinduced Jahn-Teller Distortion Dynamics.
ACS Phys Chem Au
November 2024
Rosalind Franklin Institute, Harwell OX11 0QX, Oxfordshire, United Kingdom.
Efficient photoredox chemical transformations are essential to the development of novel, cost-effective, and environmentally friendly synthetic methodologies. The concept of the entatic state in bioinorganic catalysis proposes that a preorganized structural configuration can reduce the energy barriers associated with chemical reactions. This concept provides one of the guiding principles to enhance catalytic efficiency by maintaining high-energy conformations close to the reaction's transition state.
View Article and Find Full Text PDFArchaerhodopsin 3 is an ideal template for the engineering of highly fluorescent optogenetic reporters.
Chem Sci
November 2024
University of Strasbourg, CNRS, IPCMS 23 Rue du Loess 67034 Strasbourg France
Archaerhodopsin-3 (AR-3) variants stand out among other rhodopsins in that they display a weak, but voltage-sensitive, near-infrared fluorescence emission. This has led to their application in optogenetics both in cell cultures and small animals. However, in the context of improving the fluorescence characteristics of the next generation of AR-3 reporters, an understanding of their ultrafast light-response in light-adapted conditions, is mandatory.
View Article and Find Full Text PDFDifferential Cross-Sections for the Vibrationally Excited H + HOD( = 1-4) → H + OD Reactions.
J Phys Chem A
December 2024
State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China.
Using the time-dependent wave-packet approach, we calculate the first fully converged state-to-state differential cross-sections for the H + HOD( = 1-4) → H + OD reactions on a highly accurate neural network PES. It is found that, unlike the loss of memory effect observed in the product distributions for low vibrational excitation reactions, high initial OH vibrational excitation significantly influences not only the product vibrational distribution but also the angular distribution. Furthermore, for the H + HOD( = 3,4) reactions, the total integral cross-sections maintain the pronounced oscillatory structures in the = 0 probabilities at low collision energies, which originate from the prereactive van der Waals resonances.
View Article and Find Full Text PDFUnveiling the Mechanism of Plasmon Photocatalysis via Multiquantum Vibrational Excitation.
ACS Nano
September 2024
Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea.
Plasmon photocatalysis reactions are thought to occur through vibrationally activated reactants, driven by nonthermal energy transfer from plasmon-induced hot carriers. However, a detailed quantum-state-level understanding and quantification of the activation have been lacking. Using anti-Stokes surface-enhanced Raman scattering (SERS) spectroscopy, we mapped the vibrational population distributions of reactants on plasmon-excited nanostructures.
View Article and Find Full Text PDFMillimeter-Wave and High-Resolution Infrared Spectroscopy of the Ground and Seven Lowest Fundamental States of 1-1,2,4-Triazole.
J Phys Chem A
August 2024
Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.
A combined analysis of millimeter-wave (70-700 GHz) and rotationally resolved infrared (400-1200 cm) spectra of the ground state and seven fundamental vibrational modes of 1-1,2,4-triazole is reported. While the lowest-energy vibrationally excited state (ν) is well-treated using a single-state distorted-rotor Hamiltonian, the second (ν) and third (ν) vibrationally excited states are involved in strong -type Coriolis coupling and require an appropriate two-state Hamiltonian. The oblate nature of 1-1,2,4-triazole is sufficiently close to the oblate symmetric-top limit that the analysis requires the use of A-reduced, sextic centrifugally distorted-rotor Hamiltonian models in the I representation in order to achieve low σ values.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!