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Photoexcitation

About: Photoexcitation is a research topic. Over the lifetime, 5874 publications have been published within this topic receiving 134733 citations.


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TL;DR: Thanks to the cold rotational temperature reached in the supersonic expansion, the rotational structure of the threshold ionization spectra could be resolved, and the photoionization dynamics investigated, and both rotational autoionization and predissociation were identified as decay processes in the threshold region.
Abstract: High-resolution photoionization and pulsed-field-ionization zero-kinetic-energy photoelectron spectra of CH3, CH2D, CHD2, and CD3 have been recorded in the vicinity of the first adiabatic ionization threshold following single-photon excitation from the ground neutral state using a narrow-bandwidth vacuum-ultraviolet laser. The radicals were produced from the precursor molecules methyl-bromide, methyl-iodide, dimethyl-thioether, acetone, and nitromethane by 193nm excimer photolysis in a quartz capillary and were subsequently cooled to a rotational temperature Trot≈30K in a supersonic expansion. Nitromethane was identified as a particularly suitable photolytic precursor of methyl for studies by photoionization and threshold photoelectron spectroscopy. Thanks to the cold rotational temperature reached in the supersonic expansion, the rotational structure of the threshold ionization spectra could be resolved, and the photoionization dynamics investigated. Rydberg series converging on excited rotational levels...

50 citations

Journal ArticleDOI
TL;DR: In this paper, a natural connection between mesoscale response to incident laser light and microscopic potentials is made, which describes bond-weakening as electrons are promoted from bonding to anti-bonding orbitals by photon absorption.

50 citations

Journal ArticleDOI
TL;DR: In this article, ground and excited state geometries are calculated in the gas phase and four solvents, respectively, in the context of a two-state valence bond model for charge-transfer transitions of conjugated organic molecules.

50 citations

Journal ArticleDOI
TL;DR: Amorphous Ga2O3 films have been deposited in situ on (100) GaAs layers grown by molecular beam epitaxy in ultrahigh vacuum as discussed by the authors, and the photoluminescence (PL) intensity, measured at 514.5 nm excitation wavelength, is enhanced drastically by a factor of 420 as compared to a corresponding bare GaAs surface.
Abstract: Amorphous Ga2O3 films have been deposited in situ on (100) GaAs layers grown by molecular beam epitaxy in ultrahigh vacuum. The Ga2O3–GaAs interface is stable during photoexcitation and the photoluminescence (PL) intensity, measured at 514.5 nm excitation wavelength, is enhanced drastically by a factor of 420 as compared to a corresponding bare GaAs surface. The Ga2O3–GaAs interface recombination velocity derived from a modified dead layer model is below 104 cm/s. Furthermore, the PL intensity of Ga2O3–GaAs structures approaches that of a very low interface state density (2×109 eV−1 cm−2) AlGaAs–GaAs reference structure.

50 citations

Journal ArticleDOI
TL;DR: In this article, the authors compared three techniques to extract photoelectron spectra from the wave packet resulting from the integration of the time-dependent Schrodinger equation in a finite-element discrete variable representation basis.
Abstract: We investigate the photoionization spectrum of helium by attosecond XUV pulses both in the spectral region of doubly excited resonances as well as above the double ionization threshold. In order to probe for convergence, we compare three techniques to extract photoelectron spectra from the wave packet resulting from the integration of the time-dependent Schr\"odinger equation in a finite-element discrete variable representation basis. These techniques are projection on products of hydrogenic bound and continuum states, projection onto multichannel scattering states computed in a $B$-spline close-coupling basis, and a technique based on exterior complex scaling implemented in the same basis used for the time propagation. These methods allow one to monitor the population of continuum states in wave packets created with ultrashort pulses in different regimes. Applications include photo cross sections and anisotropy parameters in the spectral region of doubly excited resonances, time-resolved photoexcitation of autoionizing resonances in an attosecond pump-probe setting, and the energy and angular distribution of correlated wave packets for two-photon double ionization.

50 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023249
2022529
2021221
2020204
2019183
2018256